Which John Guest old school dump valve?

[Cush]

Evening all. Bit of a time sensitive request here (we’re setting off in 7 days and will need it posted!)

As per the post on the tech threads my 2002 JG truma dump valve has definitely given up the ghost and im loosing water even with the pump off and the system depressurised. I’ll attach a picture of my inherited system.

The water pipes are 15mm and there is a reduction set up to accommodate the dump. I’m assuming the dump is 12mm as I can find any other size. It’s obviously not a push fit. Do you think it’s a “barbed” version?

I don’t think I have time to revamp the setup as going away soon and so was going to for like for like. Are there any other “consumables” that you think I will need? I believe that the copper pipe is 12 mm.

Finally, any recommendations for sellers that could give me the quick turnaround I need?

Sorry for the somewhat rambling post, but desperate.
Please don’t underestimate how much I appreciate your input.

Cush

 

[iandsm]

Disconnect and remove the dump valve as you are not going to need it on your trip, connect the two JG elbows which lead to it with a suitable pice of JG pipe which you should find easily available at a local caravan/ motorhome dealership if you have one or online or on eBay . Or failing that disconnect the elbows each side and push a pierce of hose over the ends of the KG pipe and secure with hose jubilee clips. Garden hose might do it if you heat the ends in very hot water.

 

[Cush]

Disconnect and remove the dump valve as you are not going to need it on your trip, connect the two JG elbows which lead to it with a suitable pice of JG pipe which you should find easily available at a local caravan/ motorhome dealership if you have one or online or on eBay . Or failing that disconnect the elbows each side and push a pierce of hose over the ends of the KG pipe and secure with hose jubilee clips. Garden hose might do it if you heat the ends in very hot water.

Thanks iandsm. Appreciate your idea. I did think about bypassing the system but in the back of my mind I couldn’t find a solution to draining the system come winter without having a bit of a spill. Any thoughts on that? I’m sure there would be a way involving hosepipe and clamps Appreciate your ideas.
Cush

 

[Trevor Wbm]

As suggested, take out the valve for the time being, but left hand joint looks to be a 15mm elbow, right hand seems to be an elbow / reducer .. swap the right hand one out for a 15mm elbow and join it up with the left hand elbow with 15mm copper or plastic.

Keep the bits you've taken out, replace the valve at your leisure and refit original joints.

 

[Cush]

As suggested, take out the valve for the time being, but left hand joint looks to be a 15mm elbow, right hand seems to be an elbow / reducer .. swap the right hand one out for a 15mm elbow and join it up with the left hand elbow with 15mm copper or plastic.

Keep the bits you've taken out, replace the valve at your leisure and refit original joints.

thank you Trevor Wbm. Your‘s and iandsm ’s suggestions do seem the most pragmatic approaches. Thank you so much.
Cush

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[berni109]

If you bypass it for now and you cant find a replacement valve as fitted you could add an equal tee with a service valve feeding to the hole in the floor or a washing machine tap tee if you have an old washing machine hose. Not exactly elegant but it's not something you are going to be looking at every day

 

[tonyidle]

Or any of these if they're nearby:

Broken Link Removed

 

[Cush]

Great ideas / lateral thinking all. Thanks berni109 and tonyidle

 

[Trevor Wbm]

Just remembered .... the valve will probably pull out easily once unscrewed, but it could well be attached to a pipe that runs out through the flooring. That may not come with it, and mine was a PITA to get reconnected. (Without it the water might appear internally somewhere, mine did that). If you don't mind getting under the van, pushing any such pipe up might be the easier way to remove the old valve.

 

[iandsm]

Thanks iandsm. Appreciate your idea. I did think about bypassing the system but in the back of my mind I couldn’t find a solution to draining the system come winter without having a bit of a spill. Any thoughts on that? I’m sure there would be a way involving hosepipe and clamps Appreciate your ideas.
Cush

I would worry about that when winter is approaching and if and when you disconnect the pipe, plenty of kitchen roll will absorb any remaining water water you have emptied the firs thank and run the pub for a few minutes

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[Cush]

Update.
I have attached a picture of my temp or longer solution. In the end, as my pipe is 15mm I used JG-Speedfit parts from screw fix and some 15mm pipe. It seems to have worked and holds pressure and includes a “sort of” dump valve. No more pump pulsing every 30 seconds in fact I didn’t hear it pulse at all when the taps are closed!

I may have a new problem which I’ll start a fresh thread for.

Thanks again for for all your help
Cush

 

[berni109]

Yeh! Looks like I get the prize.
Good job should last a lifetime

 

[Cush]

Yeh! Looks like I get the prize.
Good job should last a lifetime

You certainly do. The washing machine hose was a stroke of genius.

Wondering if I’ve messed up the pressures now as there isn’t a dead end that the dump valve may have given. To be honest, not quite sure how the dump valve worked. In my system the water can now flow from one side of the tap T to the other . Any thoughts.

 

[Orion]

Update.
I have attached a picture of my temp or longer solution. In the end, as my pipe is 15mm I used JG-Speedfit parts from screw fix and some 15mm pipe. It seems to have worked and holds pressure and includes a “sort of” dump valve. No more pump pulsing every 30 seconds in fact I didn’t hear it pulse at all when the taps are closed!

I may have a new problem which I’ll start a fresh thread for.

Thanks again for for all your help
Cush

Did you remember the pipe inserts? You’d be amazed by how many Speedfit/Hep2O installations we see where they were omitted - including a complete 5 bedroom house heating and plumbing DIY job that only started leaking 2 years down the line!

 

[Cush]

Did you remember the pipe inserts? You’d be amazed by how many Speedfit/Hep2O installations we see where they were omitted - including a complete 5 bedroom house heating and plumbing DIY job that only started leaking 2 years down the line!

I certainly did! the ones I got from screw fix had the two O rings. must Confess I nearly didnt use them but once I realised that they went in with a slight twist it was a cinch.

i assume you are i n the plumbing trade? Can you foresee any issues with the T tap providing a flow from one side of the circuit to the other? Appreciate your professional opinion.
Cush

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[Itsmcb]

Was your original valve a dump valve like the temperature sensitive valves or just a drain valve ?

 

[Cush]

Was your original valve a dump valve like the temperature sensitive valves or just a drain valve ?

It was the old style one with the yellow flap. It felt spring loaded, if that makes sense?

like this Amazon product ASIN B00H5Q63NU

 

[Itsmcb]

It was the old style one with the yellow flap. It felt spring loaded, if that makes sense?

like this Amazon product ASIN B00H5Q63NU

Ah, not seen one of those in the flesh so can't comment.

 

[Cush]

Ah, not seen one of those in the flesh so can't comment.

No worries. I can always put an inline tap on each side of the circuit

 

[Taran_Las]

Temporary solution - If you remove the drain valve and you don't have much fresh water you could just run your taps and transfer it to the grey tank.

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[mitzimad]

you now have no protection if a thermostat fails or the pipework freezes and the heater is on it probably wont go bang but its possible

 

[Cush]

you now have no protection if a thermostat fails or the pipework freezes and the heater is on.

I genuinely didn’t know that the dump valve gave me that protection. How does that work?

 

[BillyKontiki]

These valves can often be pressure relief valves and dump valve combine, so if you bypass the valve even temporarily you could be denying the system the pressure protection.

 

[mitzimad]

I genuinely didn’t know that the dump valve gave me that protection. How does that work?

its sprung loaded if pressure builds up it will lift and let the pressure out that is its primary function secondary function is its usually in the right place to drain down. i was taught all this when i took exams for fitting domestic mains fed cylinders. im a bit shakey on the physics but i belive with temp and pressure the water can release hydrogen which makes the results even more dramatic

 

[Cush]

These valves can often be pressure relief valves and dump valve combine, so if you bypass the valve even temporarily you could be denying the system the pressure protection.

its sprung loaded if pressure builds up it will lift and let the pressure out that is its primary function secondary function is its usually in the right place to drain down. i was taught all this when i took exams for fitting domestic mains fed cylinders. im a bit shakey on the physics but i belive with temp and pressure the water can release hydrogen which makes the results even more dramatic

thank you both. I don’t think I’ll be the only one that may benefit from that info. Every day’s a school day. I’ll get a new one ordered. While on my trip I’ll make sure it’s kept a close eye on and release pressure frequently. Appreciate the heads up.

thanks again BillyKontiki and mitzimad
Cush

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[Orion]

i assume you are i n the plumbing trade? Can you foresee any issues with the T tap providing a flow from one side of the circuit to the other? Appreciate your professional opinion.
Cush

I’m not familiar with your van’s plumbing but I assume the function of the valve is to drain both pipes that feed into it? If the pump isn’t running when the outlets are closed then I’d say there is no circulation taking place and you’re good to go as a temporary measure. As others have said, the original JG Truma dump valve is also a pressure relief valve which operates when the water pressure rises above 3.5 bar, so deffo fitting the correct item when you can is the way to go. In the short term you’ll probably be okay as it’s not as if you are dealing with the same situation as a domestic unvented hot water cylinder with incoming mains water pressure, large volumes of hot water and the possibility of a runaway heat source contributing to it.

 

[Cush]

Thanks Orion I be had a good blow through the old valve and it appears to let water pass from one side to he other when closed. Thanks for your input too.
Cush

 

[BillyKontiki]

As Moho and cvans are mainly tank fed the main rise in pressure building up would probably be the failure of a hot water control thermostat whether gas or electric, allowing the temperature of the water in the boiler to go beyond the system design temperature and pressure . This is where this pressure relief part of the valve comes in to play.

 

[MisterB]

Did you remember the pipe inserts? You’d be amazed by how many Speedfit/Hep2O installations we see where they were omitted - including a complete 5 bedroom house heating and plumbing DIY job that only started leaking 2 years down the line!

Or the wrong inserts used ( I had one today on site in France) wrong insert meant that that it wasn't full socket on a JG fitting - luckily it was under the caravan!!