I'm looking for some very basic and easy to follow instructions on how to replace my hot water anode.
Also, how to flush and clean my fresh water tanks.
I have always been very impressed with the detailed explanations other members have provided on posted and other matters in the past and I'm hoping for the same again.
i have a Jayco Heritage van (2005) although I have only had her a few weeks, still learning lots every day.
Seeing its a Jayco, its probably got a suburban HWS, turn all power off, turn gas off, drain the heater and remove the anode (stand a bit back you will get wet). Wrap some plumbers tape (white PTFE from bunnings) around the thread and re-install, try hard not to cross thread. Do up tight and test for leaks (fill up tank and check).
__________________
P B Crockart EX RAAF Electrician,
Aircraft Avionics tech. Senior high school teacher.
Seeing its a Jayco, its probably got a suburban HWS, turn all power off, turn gas off, drain the heater and remove the anode (stand a bit back you will get wet). Wrap some plumbers tape (white PTFE from bunnings) around the thread and re-install, try hard not to cross thread. Do up tight and test for leaks (fill up tank and check).
On most installations it is not possible to drain the water heater tank without either disconnecting the cold water inlet pipe (which is inside the RV) or removing the anode, so:-
1. Turn off all power and gas to the unit.
2. Turn off mains water or water pump as appropriate.
3. Open the cover on the water heater by turning the plastic ring to fit through the slot.
4. Lift the lever fully on the PT valve, that's the valve at the top of the heater. This will relieve the pressure in the tank. Close the valve again when water ceases to exit the outlet, this will create a negative pressure in the tank when you remove the anode and slow the egress of water through that orifice so that you don't get too wet.
5. Using a 1&1/16" or 27mm socket turn the anode nut (that's the nut at bottom centre with the small weld lump in the middle) counterclockwise to remove it.
6. Stand aside and open the PT valve again to allow the water to drain from the tank.
7. If the anode is severely corroded, then a new one will need to be fitted. If it is only partially depleted (more than half remaining), then you may return it after wire brushing the accumulated gunk off it.
A power brush is best for this purpose and you should aim for a nice shiny surface again, it will be pitted but this actually enhances its effectiveness provided it is clean.
8. It can be difficult to flush the anode detritus from the tank, you can make a small tight U shaped tube to go through the anode hole to do the job, or simply keep squirting water in and letting it drain out again.
9. Wrap 8 or 9 turns of Teflon tape tightly around the anode nut thread - if you wrap this in a counterclockwise direction looking from the nut end it will not unwrap as you screw the nut in. Don't put teflon on the first couple of threads as this will make it easier to get the thread started, take care not to cross the thread.
10. Tighten the nut firmly, open the PT valve and turn on the water. When water starts flowing freely from the PT valve, close it.
11. Shut the heater door and the job is done.
If your RV spends a fair bit of time unused, and you wish to prolong the anode's life, then consider installing a drain tap on the heater.
To do this you simply install a tee piece between the cold water inlet of the tank and the non-return valve which is normally right adjacent to it. Run a short length of pipe from the tee to under the RV and fit a 1/4 turn tap or similar.
Then, whenever you are parking the van up for a while, just open the tap and the PT valve. The water will completely drain from the tank - no water = no tank corrosion = no anode loss .
A nonreturn valve is not usually used on the Hot water inlet line
Suburbans recommendation "
Suburban recommends that a check valve not be installed directly at the inlet to
the water heater tank. This will increase weeping of the pressure relief valve."
THAT makes sense !!
The air space in the tank above the pressure releif valve is also used for pressurising the system to reduce the pump cycling [ when using ANY pumped water, both hot & cold]
Best drain the tank as much as possible before removing the anode & make some provision for water collection
AS the unit should not have a nonreturn valve, you will need to break the cold water inlet connection at it's lowest point ,after the pump outlet.
PeterQ
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-- Edited by oldtrack123 on Monday 24th of March 2014 12:15:53 AM
-- Edited by oldtrack123 on Monday 24th of March 2014 12:19:18 AM
A nonreturn valve is not usually used on the Hot ater inlet line
Suburbans recommendation "
Suburban recommends that a check valve not be installed directly at the inlet to
the water heater tank. This will increase weeping of the pressure relief valve."
The air space in the tank above the pressure releif valve is also used for pressurising the system to reduce the pump cycling [ when using ANY pumped water, both hot & cold]
Best drain the tank as much as possible before removing the anode & make some provision for water collection
AS the unit should not have a nonreturn valve, you will need to break the cold water inlet connection at it's lowest point ,after the pump outlet.
PeterQ
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-- Edited by oldtrack123 on Monday 24th of March 2014 12:15:53 AM
I would be interested to see where Suburban actually say to not have a non return valve adjacent to the water inlet.
It is common practice with all water heaters to have that non return valve so that the tank does not inadvertently drain down if a cold pipe ruptures or supply fails for some reason with a cold tap open somewhere lower than the tank.
As for the air gap above the PT valve, that's complete rubbish. The hot water outlet has a scavenging tube that is angled right to the upper inside surface of the tank to remove all air. If it didn't have this, then every time you opened a hot tap you would get a spurt of water as the built up pressure from the compressed air relieved itself.
Incidentally, the cold water inlet has a similar tube that is angled to the bottom of the tank to diffuse the incoming cold water and prevent it mixing freely with the already hot water at the top of the tank. This tube allows you to completely drain the tank via the cold water inlet as I mentioned previously, whereas draining it via the anode orifice still leaves water in the tank.
-- Edited by brian on Monday 24th of March 2014 08:44:48 AM
[1] I would be interested to see where Suburban actually say to not have a non return valve adjacent to the water inlet.
[2]It is common practice with all water heaters to have that non return valve so that the tank does not inadvertently drain down if a cold pipe ruptures or supply fails for some reason with a cold tap open somewhere lower than the tank.
[3]As for the air gap above the PT valve, that's complete rubbish. The hot water outlet has a scavenging tube that is angled right to the upper inside surface of the tank to remove all air. If it didn't have this, then every time you opened a hot tap you would get a spurt of water as the built up pressure from the compressed air relieved itself.
[4]Incidentally, the cold water inlet has a similar tube that is angled to the bottom of the tank to diffuse the incoming cold water and prevent it mixing freely with the already hot water at the top of the tank. This tube allows you to completely drain the tank via the cold water inlet as I mentioned previously, whereas draining it via the anode orifice still leaves water in the tank.
-- Edited by brian on Monday 24th of March 2014 08:44:48 AM
HI
What a load of rubbish
It seems some do not know everything after all!!! or do not have a wide range of experience??
[1] MY post regarding non return valves IS a direct copy & paste from the SUBURBAN manual ,perhaps READ IT ??
[2]perhaps more experience with RV HOT WATER systems would show otherwise?? wth a RV it would be pretty unlikely to have a tap lower than the tank & the pump is usualy quite close to the HWS & it has a nonreturn valve
Domestic systems do have a non return valve built into the filler /pressure relif valve but its prime purpose is to prevent possibly ocntaminated hot water [legionaires etc ?] bleeding back into the potable water lines !!
[3] What a load of rubbish!
Where do you think the air reserviour for pressurising the system is??
The pump usually uses the small air space in the RV HWS as a pressure reserve, just like ALL cycling pressure pumps need
IF that was not used, an air tank would have to be fitted after the pump or the pump will run on VERY SHORT ON /OFF cycles!!
How many vans have seperate AIR reserviors???
The water does not come out as a spurt MIXED with AIR
IT comes out as WATER as fast as the TAP will let it
When the pressure drops to the PUMP cut in point, the CYCLE starts over again
THAT will continue as long as the TAP is open & AFTER the tap is closed,until the sysyem is repressurised to the pump cut out point
IT is the same principles used in DOMESTIC water pressurising systems when using low pressure sources[tanks etc]
[4] [quote"] whereas draining it via the anode orifice still leaves water in the tank"[end quote] YES,, including ALL the gunk from the expired anode
The ONLY way to clean out that GUNK is by the lowest point, the cold water inlet!
water IN the anode hole, OUT the water inlet, to FLUSH out the gunk
That gunk can cause lots of blockages, if not removed, especially in the COLD water lines as the AIR pressurised water in the HWS circulates back & forth!
NOTE, vans using constant flow pumps do not have a need for AIR reserviors,as they control pressure by a BYPASS valve
Perhaps some think THAT is the only type pump used??
PeterQ
-- Edited by oldtrack123 on Monday 24th of March 2014 11:41:31 AM
-- Edited by oldtrack123 on Monday 24th of March 2014 11:43:20 AM
[1] MY post regarding non return valves IS a direct copy & paste from the SUBURBAN manual ,perhaps READ IT ??
I haven't seen that info. on any of their literature, and I have read their installation instructions pretty carefully. It is not in their plumbing guide and Matthew at Coast to Coast, who are the importers of these tanks, has never heard of it either, so how about a direct link with the location of the information on that link. Not sure how much pressure relief you could expect to get in a length of very stiff copper or John Guest piping by not having the non return valve adjacent to the tank.
[2]perhaps more experience with RV HOT WATER systems would show otherwise?? wth a RV it would be pretty unlikely to have a tap lower than the tank & the pump is usualy quite close to the HWS & it has a nonreturn valve.
Just about all caravans have a cold water tap on the drawbar, which is ALWAYS lower than the hot water tank, and whilst the pump does have a non return valve, the water from the tank could feed back through the drawbar tap without going through that pump non-return valve if one was not fitted adjacent to the hot water tank. Again, Matthew states that a non return valve must be fitted close to the tank and that the one in the pump cannot be relied upon to prevent hot water backflow
Domesic systems do have a non return valve built into the filler /pressure relif valve but its prime purpose is to prevent possibly ocntaminated hot water [legionaires?] bleeding back into the potable water lines !!
More rubbish.
First point is that very few hot water tanks have a pressure relief valve on the cold water inlet, they almost always have a pressure reduction valve. Some solar water heater tanks include a "Solatrol valve" which is a combination pressure reduction, non return valve, filter and relief valve (they have this relief valve so that cold rather than hot water is vented), but they still require a combination Pressure/temperature relief valve at the high point of the tank as well.
[3] What a load of rubbish!
Where do you think the air reserviour for pressurising the system is??
There is no air reservoir, what medication are you on? The pump simply pressurises the downstream piping and that's it. Some folks do fit an accumulator to limit cycling.
The pump usually uses the small air space in the RV HWS as a pressure reserve, just like ALL cycling pressure pumps need
IF that was not used, an air tank would have to be fitted after the pump or the pump will run on VERY SHORT ON /OFF cycles!!
How many vans have seperate AIR reserviors???
Gee... I wonder how vans with pressure pumps but no hot water tank manage, haven't seen an air tank on many of those. The pump does run on short cycles if the tap is only partially open. There is NO air left in the hot water tank once purging has taken place.
[4] [quote"] whereas draining it via the anode orifice still leaves water in the tank"[end quote] YES,, including ALL the gunk from the expired anode
The ONLY way to clean out that GUNK is by the lowest point, the cold water inlet!
water IN the anode hole, OUT the water inlet, to FLUSH out the gunk
That gunk can cause lots of blockages, if not removed, especially in the COLD water lines as the AIR pressurised water in the HWS circulates back & forth!
That's what I have been saying, except for the bit above which I have underlined, as that again is complete rubbish.
NOTE, vans using constant flow pumps do not have a need for AIR reserviors,as they control pressure by a BYPASS valve
Perhaps some think THAT is the only type pump used??
PeterQ
-- Edited by oldtrack123 on Monday 24th of March 2014 11:24:20 AM
Thanks for putting this post up, I had thought of looking at my Anode but as the van is only almost 4 months old I have been putting it off.
Reading this I got thinking that although I bought the van from yard stock in late November2013, the HWS was probably commissioned in perhaps June last year.
Anyway, got the breaker bar & 1 1/16 socket and removed it without difficulty.
On inspection, the anode was still pretty close to full length but had eroded to become rather thin right at the nut end. Rather than risk it breaking off there & falling into the bottom of the tank I replaced it with the spare that I had bought with the van.
Was I too hasty do you think or should I have tried for another 4 - 6 months out of it.
You could have put it back as it still has a lot of life left in it, it has a stainless core that stops it from breaking off, I changed one a few weeks ago for a friend that only had the stainless core left..
Thanks Bob, I wasn't aware of the reinforcing rod, figured the whole thing was zinc or whatever.
I won't ditch it then, in the spares bin it goes.
The core wire is generally not stainless, just plain steel.
The anode is normally Magnesium, sometimes Aluminium ones are used, but better to stick to Mg for maximum protection. Zinc is generally only for marine applications
Make sure that you thoroughly clean the majority of the oxidation off the rod (in the pits as well) if you are going to use it again. T
[1] MY post regarding non return valves IS a direct copy & paste from the SUBURBAN manual ,perhaps READ IT ??
[a]I haven't seen that info. on any of their literature, and I have read their installation instructions pretty carefully. It is not in their plumbing guide and Matthew at Coast to Coast, who are the importers of these tanks, has never heard of it either, so how about a direct link with the location of the information on that link. Not sure how much pressure relief you could expect to get in a length of very stiff copper or John Guest piping by not having the non return valve adjacent to the tank.
[2]perhaps more experience with RV HOT WATER systems would show otherwise?? wth a RV it would be pretty unlikely to have a tap lower than the tank & the pump is usualy quite close to the HWS & it has a nonreturn valve.
Just about all caravans have a cold water tap on the drawbar, which is ALWAYS lower than the hot water tank, and whilst the pump does have a non return valve, the water from the tank could feed back through the drawbar tap without going through that pump non-return valve if one was not fitted adjacent to the hot water tank. Again, Matthew states that a non return valve must be fitted close to the tank and that the one in the pump cannot be relied upon to prevent hot water backflow
Domesic systems do have a non return valve built into the filler /pressure relif valve but its prime purpose is to prevent possibly ocntaminated hot water [legionaires?] bleeding back into the potable water lines !!
More rubbish.
[c]First point is that very few hot water tanks have a pressure relief valve on the cold water inlet, they almost always have a pressure reduction valve. Some solar water heater tanks include a "Solatrol valve" which is a combination pressure reduction, non return valve, filter and relief valve (they have this relief valve so that cold rather than hot water is vented), but they still require a combination Pressure/temperature relief valve at the high point of the tank as well.
[3] What a load of rubbish!
Where do you think the air reserviour for pressurising the system is??
[d] I do not need medication but you need to get a little more practical experienceThere is no air reservoir, what medication are you on? The pump simply pressurises the downstream piping and that's it. Some folks do fit an accumulator to limit cycling.
The pump usually uses the small air space in the RV HWS as a pressure reserve, just like ALL cycling pressure pumps need
IF that was not used, an air tank would have to be fitted after the pump or the pump will run on VERY SHORT ON /OFF cycles!!
How many vans have seperate AIR reserviors???
Gee... I wonder how vans with pressure pumps but no hot water tank manage, haven't seen an air tank on many of those. The pump does run on short cycles if the tap is only partially open. There is NO air left in the hot water tank once purging has taken place.
[4] [quote"] whereas draining it via the anode orifice still leaves water in the tank"[end quote] YES,, including ALL the gunk from the expired anode
The ONLY way to clean out that GUNK is by the lowest point, the cold water inlet!
water IN the anode hole, OUT the water inlet, to FLUSH out the gunk
That gunk can cause lots of blockages, if not removed, especially in the COLD water lines as the AIR pressurised water in the HWS circulates back & forth!
[e] That's what I have been saying, except for the bit above which I have underlined, as that again is complete rubbish.
NOTE, vans using constant flow pumps do not have a need for AIR reserviors,as they control pressure by a BYPASS valve
Perhaps some think THAT is the only type pump used??
PeterQ
-- Edited by oldtrack123 on Monday 24th of March 2014 11:24:20 AM
HI
You must have limited experience with the real world
[1a] As I said a DIRECT copy & paste from the manual
THAT should undo all your waffle about non return valves at the tank
Perhaps Matthew should read it TOO
[2
WellIi do not know about 'just about ALL "some may .MANY do not!
Obviously you have little direct experience with a range of vans & motorhomes
it is now what Matthew said, not real life experience
Vans & motor homes have used pressure pumps for years relying purely on the non return valve in the pump!!
[2c]
AGAIN you are making broad statements
What type of HW system are YOU referring too ??
Hgh pressure DOMEStTC HWS with a coiled copper pipe heat exchanger are mandatoryly fitted with a pressure relief valve on the mains inlet line ,BUT it is not a pressure reducer
IT also acts as a NON RETURN valve as required under the standards AND a TANK filler valve
It actually bleeds back excess pressure into the tank
Similar with high pressure tank types, except they bleed the excess pressure to drain
LOW pressure HWS systems [TANK type] do require a pressure reducing valve & either a excess pressure relief valve or a standpipe type overflow
[3d]
I do not need medication, but you need to get a lttle more real llife experience with a range of vans & motor homes
[ quote ]The pump pressurises the pipe[end quote ]
THAT is a joke, how much EXTRA water would the piping hold under pressure since water is not compressable?
The plasic pipe may expand enough to hold a TEASPOON FULL!!!
]IT is that sort of stupid comment that shows you have little experience with water pressure pumps sytems [those which are PRESSURE controlled by the PRESSURE switch! NOT CONSTANT flow systems which have an internal BYPASS valve which allows recirculation of the water not required
DO YOU know the difference?
If one did as you suggest with the tap only slightly opened the pump would be rapidly CYCLING, the PRESSURE BUILD UP AND LOSS would be almost instaneous!!
IF the unit does not have a HW tank or is fitted with a NR valve, an AIR tank is ESSENTIAL[with the commonly used pumps . perhaps you need to do some googling to learn a little more since you seem to lack the practical experience
just search for AIR chambers on water pressure pumps
Even try some Van/ RV forums, the problem does come up!!" RAPID pump cycling"
Do you understand how the TWO types of pumps function??
Have you ever seen a domestic type water pressurising system for use from tanks etc ?
HAVE you ever used one when it does not have any air space left in the tank?
OVER time it is quite possible that the small amount of air in the H W tank is absorbed into the water this can/does lead to quicker cycling of the pump[REAL LlFE PRACTICAL experience]
Domestic air tanks need regular repressurising with AIR!!!
[4e]
Again lack of experience
Perhaps you can explain how the crap blocks filters & the SMALL openings in the cold water lines taps if it is not back flow[ again do a little search on forums, Then tell all,those taht you know better]!
How bad ,will depend on the distance of the hw cold inlet tee off from the main cold water lines, if that distance is long the crap will / may just circulate back k& forth!!
PeterQ
-- Edited by oldtrack123 on Monday 24th of March 2014 04:12:50 PM
Magnesium will have a very short life if used with highly mineralised water
Aluminium is often used in that situation, BUT some find the water has an odour
Of course like ALL hot water systems it is inadvisable to drink the water
You will find they general loss material close to the thread first , this is to be expected as the small area of non lined steel of the tank & inlet socket are reacting
THAT area can become quite bare, but is ok, as long as solid Magnesium is left on the remainder
PeterQ
-- Edited by oldtrack123 on Monday 24th of March 2014 04:25:51 PM
Thanks Bob, I wasn't aware of the reinforcing rod, figured the whole thing was zinc or whatever.
I won't ditch it then, in the spares bin it goes.
The core wire is generally not stainless, just plain steel.
The anode is normally Magnesium, sometimes Aluminium ones are used, but better to stick to Mg for maximum protection. Zinc is generally only for marine applications
Make sure that you thoroughly clean the majority of the oxidation off the rod (in the pits as well) if you are going to use it again. T
Whatever brian without a capital B, I'm not sure it really matters if it is stainless or just plain steel as you put it, it is there to stop the anode from breaking away from the nut..
I'm kinda over all this nit picking that goes on here at Techies Corner.. all it does is turn members off asking questions and offering help..
Whatever brian without a capital B, I'm not sure it really matters if it is stainless or just plain steel as you put it, it is there to stop the anode from breaking away from the nut..
I'm kinda over all this nit picking that goes on here at Techies Corner.. all it does is turn members off asking questions and offering help..
Hi Bob
I have seen BOTH, Stainless & plain carbon steel.
But you are correct THAT is a MINOR detail compared to some of the wrong statements often made!
But you are correct THAT is a MINOR detail compared to some of the wrong statements often made!
PeterQ
Come on Peter, have you really seen Suburban hot water service anodes with stainless steel cores?
We were discussing Suburban anodes here, but I seriously doubt that you would ever see a stainless cored one for any hot water tank.
Who makes them?
Who sells them?
We both know that manufacturers will not spend money that they don't need to.
What possible gain could be had by using a stainless inner core?
Firstly, the core is not in contact with the water other than at the very ends, so corrosion could only occur there.
Secondly, the core would be totally protected against corrosion by the anode anyway, so there is absolutely no reason to use stainless steel.
Thirdly, Stainless steel suffers from crevice and pitting corrosion which is not protected by the anode, so there is a distinct possibility of a stainless core failing where it meets the nut.
But you are correct THAT is a MINOR detail compared to some of the wrong statements often made!
PeterQ
Come on Peter, have you really seen Suburban hot water service anodes with stainless steel cores?
We were discussing Suburban anodes here, but I seriously doubt that you would ever see a stainless cored one for any hot water tank.
Who makes them?
Who sells them?
We both know that manufacturers will not spend money that they don't need to.
What possible gain could be had by using a stainless inner core?
Firstly, the core is not in contact with the water other than at the very ends, so corrosion could only occur there.
Secondly, the core would be totally protected against corrosion by the anode anyway, so there is absolutely no reason to use stainless steel.
Thirdly, Stainless steel suffers from crevice and pitting corrosion which is not protected by the anode, so there is a distinct possibility of a stainless core failing where it meets the nut.
Fourthly, it costs more to produce.
Whats your point brian without a capital B.
WTF does it matter if an anode has a stainless core or a bamboo core
You are friggen nit picking and making Techies Corner a place to stay away from for members for fear of being picked on by the likes of you..
Grow up or go back to the school yard and pick on the little kids you are becoming a PITA..
But you are correct THAT is a MINOR detail compared to some of the wrong statements often made!
PeterQ
Come on Peter, have you really seen Suburban hot water service anodes with stainless steel cores?
We were discussing Suburban anodes here, but I seriously doubt that you would ever see a stainless cored one for any hot water tank.
Who makes them?
Who sells them?
We both know that manufacturers will not spend money that they don't need to.
What possible gain could be had by using a stainless inner core?
Firstly, the core is not in contact with the water other than at the very ends, so corrosion could only occur there.
Secondly, the core would be totally protected against corrosion by the anode anyway, so there is absolutely no reason to use stainless steel.
Thirdly, Stainless steel suffers from crevice and pitting corrosion which is not protected by the anode, so there is a distinct possibility of a stainless core failing where it meets the nut.
Fourthly, it costs more to produce.
Whats your point brian without a capital B.
WTF does it matter if an anode has a stainless core or a bamboo core
You are friggen nit picking and making Techies Corner a place to stay away from for members for fear of being picked on by the likes of you..
Grow up or go back to the school yard and pick on the little kids you are becoming a PITA..
Giving Peter a bit of his own medicine back Bob. You do your fair share of it too. But I agree that I am becoming a bit bored with this.
Maybe we could start a new thread called the brian, Peter and Bob stir debate, where we could all put our thoughts forward regarding posts on Techies Corner and pull each other to pieces without making drawn out, nit picking, boring, uninteresting posts on simple question threads.
That way Peter and I could gang up against you and you and Peter could gang up against me and you and I could really get stuck into Peter without involving all the other members of this forum..
OR
We could accept things each other says so long as it is generally right and answers the OPs question..
Just a thought in the interest of the other members of this very happy community.
Maybe we could start a new thread called the brian, Peter and Bob stir debate, where we could all put our thoughts forward regarding posts on Techies Corner and pull each other to pieces without making drawn out, nit picking, boring, uninteresting posts on simple question threads.
That way Peter and I could gang up against you and you and Peter could gang up against me and you and I could really get stuck into Peter without involving all the other members of this forum..
OR
We could accept things each other says so long as it is generally right and answers the OPs question..
Just a thought in the interest of the other members of this very happy community.
Nah...I'll leave it to you two, if you wish to post inaccurate info and then so vigorously object to that being (what I thought to be) innocuously clarified in the course of the rest of my post, it's time for me to leave you to it.
brian wrote: Giving Peter a bit of his own medicine back Bob. You do your fair share of it too. But I agree that I am becoming a bit bored with this.
Well
It looks like you have ran out of Bul$*#t! or squibing out So far most of your answers are BULL-----
The subject did seem to develop far wider than just Suburban HWS Anodes.
Do you understand yet WHY an air chamber IS Necessary with a pressure switch controlled variable flow pump ?
Did you KNOW that both types of pumps are available?
You do need to get out there & gain some ACTUAL experience with the various types of pumps, then you will understand why MANY need an AIR pressurising tank .
It does not have to be very big for a van/ motor home, I MIGHT just find a link to one for you 500mL.<1Lt is about enough
Domestic style units have around a 20Lt tank, AIR pressuresed in a bellows to around 1<2Bars
Well what do you know ,HERE is such a link, TO probably the most common pump used by VANs &MHs
IF you look carefully you will see the refrence to an" ACCUMULATOR ,That IS the pressure stabilizing unit
you will even see it in the diagram
BUt No need for one If the HW tank can /does serve the same pupose[ IF A NR VALVE is not fittted]AS many/ most DO!!
What do you have to SAY NOW after reading the other link, about the NR valve ,that your mate said MUST be fitted?
Strange that that link Does not recommend a NRvalve, in fac tindicates one should not be fitted.
I wonder how many VANS or MHs you have ACTUALLY SEEN with a NR valve fitted at the HW tank inlet[ especially since the makers do not require one] ???
SHURFLO Pumps are about the MOST common pump that has been used for many YEARS in vans & motor homes.
BUT I assure you, you would go crazy & SO WOULD the pump IF An air space is not available for other than those pumps who have a flow bypass type pressure regulator.
BUt for the benifit of others, I might just give a little further info on accummlators
They can be in many forms
Some use a piston type plunger backed by a spring to obtain the pressure accumulation effect,
Other use a diagraphm in a chamber,. the diaphragm again is backed by a spring
Even a long lenth of blanked of PIPE will give some effect [IF VERTICLE] the problem with that is the air lost to absorption needs to be replace or the effect is lost
Any thing that can absorb the pressure & hold a quanity of water will do the job!!
Even an anti WATER hammer unit would have a SMALL effect
But the larger the accummulator the less cycling of the pump
Accumulators have a long history in pressurising systems or absorbing sudden repeating PUMP STROKES [reciprocating pumps etc]
However a means of replacing the air lost by ABSORTION in the water is needed [IF the AIR is in direct contact with the water.]
This can happen over time with ANY direct water to air contact system,s including the HW system
PeterQ
So don't squib out, come back IF you can SHOW other wise.
I am sure many would like to see the confusion cleared up??
om
-- Edited by oldtrack123 on Monday 24th of March 2014 09:30:33 PM
-- Edited by oldtrack123 on Monday 24th of March 2014 09:33:46 PM