# Hymer B564 Boiler question



## olipowell (Jul 19, 2014)

Hi everyone,

This is my first post on this forum. I'm sure the answer to this question is out there somewhere, but cannot find a consistent one when searching.

We have have recently purchased our first MH (1994 Fiat Hymer B564). We love it and generally speaking its in great nick for its age.

I do have a couple of issues that are bothering me but the main one is the drip from what I think is the ventilation tube from the Truma boiler.

The docs I have are all in German and the english pages from what I can tell have been ripped out (very helpful!).But looking at the diagrams I believe this is related to the Ventialtion tube. 

It is a red tube off a T junction (not sure if its a valve) that come off the hot water outlet. It does not drip all the time, just when the water has been used. The tube does come up from the hot water outlet and the top of the bend is above the top of the water tank. 

Is this normal behaviour? or is there something that need attention.

I'm not sure of the boiler model as its not marked on the docs.

Any help much appreciated.

Cheers
Oli


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## rayc (Jun 3, 2008)

> [quote="olipowell"
> I do have a couple of issues that are bothering me but the main one is the drip from what I think is the ventilation tube from the Truma boiler.
> 
> Oli


I think you are talking about the red pressure release valve that would activate when an over pressure situation occurs and vent the water or steam to the outside.
it is possible in this hot weather that if you heat the boiler to 660 degrees that the valve may weep and reduce the pressure that has built up due to water expanding when hot. Of course the valve could be faulty and have a slight leak. In any even they are relatively cheap.


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## olipowell (Jul 19, 2014)

Thanks rayc,

I'm not sure. At the moment it will leak even though the boiler is not on. Its not a constant drip, just when the water has been used, it will drip for the following hour or so.


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## Bill_OR (Feb 6, 2010)

Here's a link to the Truma documentation page and there is a link from there to the older equipment.
Perhaps you can work out the model from the shape of the boiler and then download an English manual.


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## philoaks (Sep 2, 2008)

If its not heat related as suggested by rayc then I would think it's pressure related. When you've just used water the system will be pressurised. I'm not sure if your van uses a pressure switch or micro switches on the tap but either way immediately after using water there will be pressure in the system that gradually reduces over a period of time. I would imagine the pressure release valve on the boiler is leaking and needs replacing.

Phil


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## olipowell (Jul 19, 2014)

Thanks all,

Makes sense that its a pressure related issue.
Looking at the valve/connector, it doesn't look like the diagrams shown. So perhaps somebody has made a modification there. If it is the breather valvle it looks as though it should be directly connected to the boiler tank. The "T" in the pipe is further along the outlet pipe. I will look tonight.

The link to the documentation is helpful, thank you.

Just to confirm though, is this working as designed, is the valve doing what it should by letting water out? or is this telling me that the system pressure is too high?

Oli


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## philoaks (Sep 2, 2008)

I would think the valve has weakened and is allowing water to flow at a much lower pressure than originally designed for. The purpose of the valve is to release pressure should the boiler overheat where the pressure of steam created will be much higher than the pump will be producing.


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## olipowell (Jul 19, 2014)

Thanks all for your help,
I think the part I'm looking for is in the following diagram (17). It tells me its a Truma non return valve.

Do you think this is the part I'm looking for?

LeisureShops


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## vicdicdoc (May 14, 2005)

Its quite possibly the non return valve . . For the cost of a replacement it might be worth fitting a new one & see if problem is cured, if not THEN look further . . . They do tend leak or fail due to age.


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## olipowell (Jul 19, 2014)

Does anyone know how to remove the hose clamps on the hymer?
They don't have a Philips head and seem to have a tiny hook that is almost impossible to grab hold of.


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## philoaks (Sep 2, 2008)

> Does anyone know how to remove the hose clamps on the hymer?
> They don't have a Philips head and seem to have a tiny hook that is almost impossible to grab hold of.


Any chance of a photo of the clamps? I'm wondering if they are single use and have to be cut off and replaced.


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## olipowell (Jul 19, 2014)

Hi

I can't attach photos from iPhone. Can I email to you?

Thanks
Oli


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## philoaks (Sep 2, 2008)

This photo has come from Oli and is the hose clamp on his water heater.

To me it looks like a single use clip which is tightened using a special pair of pliers. The only way to remove them is to carefully cut through the band and peel it off. They can then be replaced with a normal hose clip.

Anyone other ideas will be gratefully appreciated by Oli I'm sure.

Phil


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