Water overflows constantly when pump is on

[Abgs]

New problem … when I turn on a tap I get a very poor flow and i can hear and see water coming out through the overflow pipe under the van. This only happens when the pump is operating.

Tank is about 1/4 full. If I turn the valve on the fresh water tank to lower it to 20 litres, then water flows out through the overflow. So pretty sure its not that valve at fault

I have recently had to disconnect the habitation battery so I am wondering if my Combi 6 heating boiler has automatically opened an overflow valve but … I can’t find the valve anywhere.

Hymer Exsis-i 588 - 2018.

Anyone got any ideas?


TIA

 

[David and Sally]

The Truma has an automatic dump valve that dumps boiler water below 3 deg. Sounds like that is open. I would have no idea where it on your van but it will have an outlet under the van.

The hot circuit has drained but you are pumping water into it when the pump is running, it then continues to dump the water as the pump is running.
That's my guess.

Looks like this

<Broken link removed>

 

[monzer]

Yes, as above. The dump would have activated when the battery was disconnected. Now any time you try to run water it will flow out until you reset the valve on boiler.

 

[monzer]

Valve may look like this....

 

[Lenny HB]

Valve may look like this....

View attachment 440964

Those valves have not been fitted for 10 years or more the modern ones are mechanical no electrical connections.

^{_{Subscribers  do not see these advertisements}}

 

[MikeD]

The manual valve should look like this. Its usually very near the boiler.

 

[denisejoe]

It will be above where the water is coming out

 

[Abgs]

The hot circuit has drained but you are pumping water into it when the pump is running, it then continues to dump the water as the pump is running.

That would make sense and so I've been hunting for the valve but I just can't find it. The boiler is under the dinette seat so easy to access. I've looked at the instruction manual for the boiler and it shows a picture of a valve similar to the one in the post above but where they've hidden it I don't know!

 

[Abgs]

It will be above where the water is coming out

Its coming out of the overflow below the fresh water tank - whether that overflow is also connected to the boiler I can't tell.

 

[Abgs]

The manual valve should look like this. Its usually very near the boiler.

View attachment 440970

Can't see one of those either.

^{_{Subscribers  do not see these advertisements}}

 

[MikeD]

It's used to drain the boiler down for winter storage. Follow the white pipe which is attached to the boiler in the bottom RH of your picture.

I am sure the black pipe is the gas supply.

 

[Lenny HB]

Are you sure it is coming out of the tank overflow?
A common problem is the elbow on the hot water outlet on the Combi boiler it has an aeration valve that allows air out when the boiler is filled these have a habit of sticking allowing water to flow out when the pump is running.
A new valve is about a tenner, if it is the valve you could try soaking it in hot white vinegar as it's normally a calcium build up that causes the problem.

 

[Lenny HB]

The manual valve should look like this. Its usually very near the boiler.

View attachment 440970

Not on a Hymer those valves are normally only fitted to Brit vans, German vans always fit the frost control valve.

 

[Abgs]

Are you sure it is coming out of the tank overflow?

I can only see one overflow pipe under the van from in the fresh water tank area.

A common problem is the elbow on the hot water outlet on the Combi boiler it has an aeration valve that allows air out when the boiler is filled these have a habit of sticking allowing water to flow out when the pump is running.
A new valve is about a tenner, if it is the valve you could try soaking it in hot white vinegar as it's normally a calcium build up that causes the problem.

Is that the valve I've marked here?

Not on a Hymer those valves are normally only fitted to Brit vans, German vans always fit the frost control valve.

The Trauma manual says 'FrostControl (safety/drain valve – UK version optional)' but my Hymer was German market supplied then imported to the UK at 12 months old. So I must have the valve somewhere. I've run out of floor hatches to lift and obvious places to look!

 

[David and Sally]

That's a water outlet, not a valve.

^{_{Subscribers  do not see these advertisements}}

 

[mitzimad]

it will be directly above the pipe thats under the van

 

[Lenny HB]

Is that the valve I've marked here?

Yes that's the one.
Hymer normally fit the frost control valve next to the cold drain tap often near the locker opening.

 

[Abgs]

That's a water inlet, not a valve.

Ahh .. I was referring to Lenny's comment - 'elbow on the hot water outlet on the Combi boiler it has an aeration valve'

 

[Lenny HB]

That's a water inlet, not a valve.

If you are referring to the one he has circled it is the hot water outlet with a valve as per my post #12

 

[David and Sally]

If you are referring to the one he has circled it is the hot water outlet with a valve as per my post #12

I thought he was referring to the dump valve. I have also corrected my post.

^{_{Subscribers  do not see these advertisements}}

 

[Abgs]

Thanks all - Another trip over to the storage yard on Tuesday to find it then!

 

[Lenny HB]

The overflow pipe from the hot water inlet you can fold the pipe in half and clamp it with a cable tie, try it and see if that stops it.

 

[Googlebot]

Are you sure it is coming out of the tank overflow?
A common problem is the elbow on the hot water outlet on the Combi boiler it has an aeration valve that allows air out when the boiler is filled these have a habit of sticking allowing water to flow out when the pump is running.
A new valve is about a tenner, if it is the valve you could try soaking it in hot white vinegar as it's normally a calcium build up that causes the problem.

What might be happening is as Lenny says above. However mine stuck shut and wouldn’t let air in, this meant that even with the valve open the water wouldn’t drain unless the pump was on as you describe.

I have a feeling on the newer models, the drains are under a hatch under the dining table where I can see you have the carpet down.

To fix my valve I just pulled it off the push fit and blew down the vent pipe which made it come free.

 

[Manic]

I would think it’s the circled expansion valve, I had to change mine (on the van of cause) because it was dripping, small valve getting stick.

 

[bigalw35]

please don't ask why, but trust me IT DOES, I've got Hymer B680 and if the voltage drops below 10 volts the boiler dump valve opens and drain's the boiler, of course if you use the hot tap after that (without resetting the dump valve) it will flow from the boiler to the outside world. I checked the Hymer manual and this is correct ?????

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

please don't ask why, but trust me IT DOES, I've got Hymer B680 and if the voltage drops below 10 volts the boiler dump valve opens and drain's the boiler, of course if you use the hot tap after that (without resetting the dump valve) it will flow from the boiler to the outside world. I checked the Hymer manual and this is correct ?????

As I said before they don't use those valves any more not for at least 10 years, the dump valves are mechanical now.

 

[Abgs]

I have a feeling on the newer models, the drains are under a hatch under the dining table where I can see you have the carpet down.

Ahhh ... that'll be this one then !! All reset and working now.

No idea why I didn't lift the carpet before. Doh!

Thanks everyone.

 

[Lenny HB]

Ahhh ... that'll be this one then !! All reset and working now.

No idea why I didn't lift the carpet before. Doh! View attachment 441410

Thanks everyone.

View attachment 441409

Silly boy.

 

[Abgs]

Silly boy.

I think I'd plonked my tool box down on the floor over the hatch there whilst I had the dinette seats apart and didn't think to move it ....

It's all a good education - !