Not able to drain Truma heater (1 Viewer)

Affiliate links here may earn MHF compensation
May 20, 2015
361
319
Newbury
Funster No
36,484
MH
AS Kingham
Exp
Since 1970
A repeat of last year’s problem. Then I changed the automatic dump valve for a manual one, which made no difference. Opened it this weekend and about a litre drained into a bucket, with all taps opened. If I turn pump one, there’s still water in the main tank, it pumps out of the dump valve but stops when pump turned off. An airlock seems obvious problem but system works fine rest of time. Live in the sticks so could drive around to see if I leave a trail of water, when the monsoons have stopped. Oh and reversed into bucket at end, 0.99p B&Q jobbie 15 years old which naturally shattered. Just not made to last.
Thanks in advance
 
Dec 10, 2013
3,431
12,809
South Staffs
Funster No
29,333
MH
Pilote P740GJ
Exp
Since 2013
I dumped my water heater today with all the taps open and thought that there wasn’t much water come out.
I just remove the shower head and attach a small air compressor using one of of those tapered attachments they use for blowing up plastic balls, just push it into the shower hose.
I always drain my main tank first, that’s just got a bung in the bottom of tank.
 
Upvote 0
Nov 13, 2011
1,509
3,783
Lincolnshire
Funster No
18,889
MH
PVC
Exp
30 years
Not sure what the issue is. "there's still water in the main tank".
You are never going to drain the main water tank via the system drain valve.
It is only designed to drain the hot/cold pipework.
Anything below the valve level will need to be drained via the tank drain tap.

Geoff
 
Upvote 0
OP
OP
solaris
May 20, 2015
361
319
Newbury
Funster No
36,484
MH
AS Kingham
Exp
Since 1970
Thanks for your comments. To respond to your thoughts:

Van is 2018, I have flushed the system about 2020 with proprietary cleaner. Mentioned water in tank as have an underslung tank with submersible pump with non return valve. Was trying to demonstrate that water flows freely through the Truma and the non return valve means water from Truma cannot drain back into tank. When freezing weather is forecast I also open cold tank drain tap but as I discovered last year this still leaves water in Truma, found out on refilling when system came up to pressure far too quickly. Like idea of blowing air through shower.

Because we use van all year I tend to drain Truma between trips in winter for safety and also have a heater in the van.

You have all given me ideas to consider, thanks again.

Subscribers  do not see these advertisements

 
Upvote 0
Oct 10, 2018
2,036
1,162
Bracklesham Bay, West Sussex
Funster No
56,646
MH
PVC
Exp
Since 2005
solaris It may be worth checking if there is another (inline ? ) non-return valve fitted near the Truma boiler water supply inlet , as , if there is one fitted in this location this could be the cause of it not fully draining down , as they normally do , with the taps being left open, with the pump turned off , to allow air in for the Truma to drain .
 
Upvote 0
Jun 5, 2020
113
245
Derbyshire
Funster No
71,470
MH
Dethleffs Advantage
Exp
Since 2020
I drained down the fresh water tank and opened the Truman drain on the water heater over the weekend. All the taps, including the shower, were open half way between hot and cold and a flood of water ensued from beneath the van. However after that had finished and I was moving around the van removing and cleaning the carpets, a second wind of water started draining from the heater, I presumed an airlock - perhaps the OP needs to rock the van to encourage this?
 
Upvote 0

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top