Hymer 522 Van "Heater drain valve" (1 Viewer)

hallii

Free Member
Apr 23, 2010
61
1
Worcestershire
Funster No
11,214
Exp
20 or so
I am slowly finding my way around my 522 Van having had it for a couple of weeks.

After much searching I found the automatic heater drain valve which the book tells me will open at 8 degrees celsius to protect the heater from frost.

But what an awkward place to reach, I have visions of this valve opening in the depths of a cold night in the mountains and having to crawl into the garage, in the frost, to close it so the heater can be used.

It seems a bit daft to me.

Any comments?

Geoff
 

Geo

Trader - Funster
Jul 29, 2007
11,757
14,565
Mansfield,Notts
Funster No
35
MH
Autotrail Tracker FB
Exp
45 +years with breaks
It wont happen that often
It is assumed that if your up in the mountains @ -8 degrees you will have your heating on:Eeek:
also the hot water will be on so the valve will stay shut
If its the normal type with the drop down drain plunger
a few on here suggest putting a sprig type cloths pegg around the plunger to prevent it from dropping down (thats how it drains)
Don't forget to remove the peg when in storage as you will lose the protection it offers
Others have suggested removing the auto valve and fitting a manual version
Geo
 
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hallii

hallii

Free Member
Apr 23, 2010
61
1
Worcestershire
Funster No
11,214
Exp
20 or so
Thanks Geo, I noticed a hole is drilled right through it and I did consider putting a length of nylon cord through it and tying it off somewhere.

Clothes peg will do fine for me though!

I will probably wait until it happens and make a decision then, as you say, the heating will be on so it shouldn't happen to often.

I note you say "-8C" (minus 8) my book says 8 C but I will have another look.

Geoff

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Robinhood

Free Member
Mar 7, 2010
158
0
Sherwood Forest
Funster No
10,535
MH
A Class
Exp
20 years
Thanks Geo, I noticed a hole is drilled right through it and I did consider putting a length of nylon cord through it and tying it off somewhere.

Clothes peg will do fine for me though!

I will probably wait until it happens and make a decision then, as you say, the heating will be on so it shouldn't happen to often.

I note you say "-8C" (minus 8) my book says 8 C but I will have another look.

Geoff

The quoted temperatures for dumping seem to vary somewhat by year of manufacture and model of the unit being protected.

Recent ones, however (say up to 5 years old, and I think yours should be in that category) tend to quote dump at less than 4 degrees, and the valve will not 'hold' if initial closure is attempted below 8 degrees.

Note though that the unit WILL NOT DUMP if the heating circuit is in use (hot water and/or heating on a Combi) - we tend to leave ours at least on low water heat overnight in winter - and the valve WILL HOLD an initial closed position at any temperature in the same circumstances (i.e. if it is really cold and you want to fill an emptied system, you can turn the heating on before filling - note, space heating only not water heating recommended until filled).

Must admit that if I fill at home before setting off in winter, I will use the peg trick rather than turning on, even though I'm on hook up.

DON'T leave the peg on anything but temporarily - it could be an expensive error.
 

EMS

Jan 8, 2010
200
180
Hants Sussex border near
Funster No
9,860
MH
Coachbuilt Low
Exp
Started 2009!
Leisure battery off

Our 572 has the same system (the valve is easy to get to, inside a cupboard under the floor), note that when we leave the van in storage I switch off the leisure battery to prevent it discharging at the control panel under the front passenger seat and this has the effect of opening the dump valve.
If you do not turn the leisure battery off you run the risk of flattening the battery as there is a continual drain for the gas detection etc.
 

JeanLuc

Free Member
Nov 17, 2008
3,304
2,199
Warwickshire
Funster No
4,952
MH
Hymer B630 Star-Line
Exp
Since 2007
The Truma frost protection valve requires a 12V supply to keep it closed. Once you switch off the Elektroblock EBL (in a Hymer for example) the valve opens. Switching off the 12V at the control panel does not have this effect as the frost valve is wired directly from the EBL.
As has been mentioned, the valve normally opens when the temperature falls below + 4℃ but cannot be re-set until the temperature reaches + 8. I have overcome this (when filling up with water after the van has not been used for a couple of weeks in winter) buy holding the valve body for a couple of minutes. The warmth from my hand is often enough to allow a reset.
The valve will not open during the night if you leave the system ticking over on minimum setting. The temperature in the cabinet where the Truma is located will remain quite warm.

Philip

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alanheath

Free Member
Oct 29, 2012
5
2
Warszawa, Poland
Funster No
23,480
MH
Hymer Van
Exp
2
I cannot find it on my 522 - it does not seem to be where the booklet says it should be (fig 230, page 188).

It is only 29 October now. I hope that this is not a sign of things to come!
 

Robbo_2021

Free Member
Nov 16, 2021
4
1
Funster No
85,467
MH
Hymer Van 522
Yes I realise, but I have just joined.
I am similarly having trouble finding the drain valve for our Hymer 522.
 

Robbo_2021

Free Member
Nov 16, 2021
4
1
Funster No
85,467
MH
Hymer Van 522
Hi Bigalw35 and BusyBuilder
Thanks for your advice.
I will check under the wardrobe and cupboard floors.

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Lenny HB

LIFE MEMBER
Oct 18, 2007
53,239
149,304
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
Another way of finding it is to grovel under the van and take note of all pipes that come through the floor it will probably be a 10mm clear pipe.
 
Oct 13, 2016
1,050
897
Grays - Essex - UK
Funster No
45,568
MH
Mercedes Hymer B680
Exp
Been moho’ing for a time now
Another way of finding it is to grovel under the van and take note of all pipes that come through the floor it will probably be a 10mm clear pipe.
and there's probably 3 pipes, hot, cold and boiler, as Lenny says there probably about 10mm, normally under the boiler
 

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