The Auto-Sleeper Motorhome Owners Forum (ASOF)
Would you like to react to this message? Create an account in a few clicks or log in to continue.

Truma Cascade immersion - PRV replacement

+3
inspiredron
Paulmold
scmarf
7 posters

Go down

Truma Cascade immersion - PRV replacement Empty Truma Cascade immersion - PRV replacement

Post by scmarf Sat Nov 30, 2019 6:49 pm

Just replaced the Truma Cascade Immersion heater pressure relief valve on the Clubman. As suspected, after 21 years, it wasn't keen on coming out. It started to unscrew but then sheared leaving the threaded bit in the heater. It took a while but by using a small file and hacksaw blade to create a screwdriver slot in it (without damaging the thread) and gently hammering a large screwdriver in, I managed to unscrew the broken end.
Then I used a vacuum cleaner and small brush to remove the swarf.
Then I cut a groove in a bolt and gradually ran that down the hole to clean out the thread.
I didn't want to put any grease or anything on the thread as I didn't want it getting in the water.

Hope this helps anyone trying to do the same job smile! 

Truma Cascade immersion - PRV replacement Prv_in10
Truma Cascade immersion - PRV replacement Prv_to10
Truma Cascade immersion - PRV replacement Prv_bo10
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Paulmold Sat Nov 30, 2019 8:02 pm

I did that job about 8 years ago on our Symphony. As you say the important thing is not to damage the thread. I tried the large screwdriver like you but it wouldn't budge so I did it by drilling the broken piece left in , increasing size of drill a little at a time until the last bits fell out before hitting the thread.

_________________
Nice to be important but more important to be nice
Paulmold
Paulmold
Donator
Donator

Male

Posts : 26679
Joined : 2011-02-21
Member Age : 73
Location : North East Wales
Auto-Sleeper Model : Sussex Duo
Vehicle Year : 2010

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by inspiredron Sat Nov 30, 2019 9:10 pm

Amazing job! Well done. Keeping swarf out of the heater must have been a huge challenge! How much does a new heater cost? 🙄

_________________
Best wishes - Ron
inspiredron
inspiredron
Member
Member

Male

Posts : 3436
Joined : 2012-06-02
Member Age : 83
Location : Ellesmere, Shropshire
Auto-Sleeper Model : Lancashire
Vehicle Year : 2012

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by gassygassy Tue Dec 03, 2019 12:10 pm

Well done from a retired gas boiler engineer. I am properly impressed. And showing the invoice from Truma was very encouraging, that they don't overcharge for parts. At least, not that part anyway! A bit worrying though that it should seize, I have never had that trouble on domestic gas boilers. You don't say what the two metals were, presumably they are incompatible?
Worried now that mine might seize. . . . . .

_________________
complexity is the enemy of reliability
gassygassy
gassygassy
Donator
Donator

Male

Posts : 1241
Joined : 2019-06-21
Location : Lutterworth
Auto-Sleeper Model : 1 Bourton 1 Polensa
Vehicle Year : various

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Paulmold Tue Dec 03, 2019 12:31 pm

Don't panic gassy, we are talking about Cascade water heaters here (taken over by Truma way back in 1999, that's why the packaging is from Truma), made by Carver. The pressure valve is made of a  nylon/polythene inserted into an aluminium frame.

Here's the offending item 

https://images.app.goo.gl/SumhSYVT88uFLAi86

_________________
Nice to be important but more important to be nice
Paulmold
Paulmold
Donator
Donator

Male

Posts : 26679
Joined : 2011-02-21
Member Age : 73
Location : North East Wales
Auto-Sleeper Model : Sussex Duo
Vehicle Year : 2010

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by scmarf Tue Dec 03, 2019 2:27 pm

gassygassy wrote:Well done from a retired gas boiler engineer. I am properly impressed. And showing the invoice from Truma was very encouraging, that they don't overcharge for parts. At least, not that part anyway! A bit worrying though that it should seize, I have never had that trouble on domestic gas boilers. You don't say what the two metals were, presumably they are incompatible?
Worried now that mine might seize. . . . . .
I replaced it because the screwdriver slot had broken. I guess the plastic hardens up over 21 years. It was still possible to operate it by taking the cover off but with the replacement valve costing less than £10, my OCD won out hugegrins .
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Carver cascade connections.

Post by George Collings Thu Dec 19, 2019 12:49 pm

On my 21st year of mono ownership.  All the Cascade water connections are plastic and harden with age. Best practice is to renew every five years.  As described drilling out until the bits fall apart works.  The parts appear to be disapearing from dealer shelves. Mine are due . The critical one is the one way valve that keeps heated water in the boiler.  Its likely  the threads are standard plumbing sizes and  similar items  might be found at a plumbers merchants. I have  one in my bits box and will see if I can identify the thread.
George Collings
George Collings
Member
Member

Male

Posts : 71
Joined : 2019-04-02
Location : South Devon
Auto-Sleeper Model : Medallion
Vehicle Year : 1997

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by scmarf Mon Dec 30, 2019 11:06 am

Next challenge: Giving the plastic cover a coat of paint while it's off. Anyone got experience of this? According to the internet I need a 'Adhesion promoter', some paint and some lacquer.
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Roopert Mon Dec 30, 2019 1:09 pm

Yes - I did mine with just Hycote plastic primer and ordinary rattle-can cellulose (or whatever substitutes for that in the solvent-based paints these days), colour-matched to the rest of the van.

I was very sceptical and expected it to bubble off the first time the Cascade lit up! But it didn't, and it looked as good when I sold the van 2 years later. I should add though that mine looked (and physically was) quite rough before the spraying, so adhesion of the paint was very good.
Roopert
Roopert
Member
Member

Male

Posts : 3799
Joined : 2019-03-10
Location : South East
Auto-Sleeper Model : Trooper
Vehicle Year : 2005

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by modelman Mon Dec 30, 2019 2:53 pm

I worked a lot with plastics, & as Roopert stated above, a plastic primer is required before paint as it slightly dissolves/melts the surface leaving a good substrate for paint adhesion, failure to do so & there's a good chance that your new paint will flake off. It will DRY, but not stick!!

_________________
I DO have to grow old, I DO NOT have to grow up!
modelman
modelman
Donator
Donator

Male

Posts : 5313
Joined : 2011-09-16
Member Age : 78
Location : Barnsley,S/Yorks
Auto-Sleeper Model : Amethyst
Vehicle Year : 2003

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Paulmold Mon Dec 30, 2019 5:09 pm

I think you'll find the cascade ' cover' is the vent which is cast aluminium.

_________________
Nice to be important but more important to be nice
Paulmold
Paulmold
Donator
Donator

Male

Posts : 26679
Joined : 2011-02-21
Member Age : 73
Location : North East Wales
Auto-Sleeper Model : Sussex Duo
Vehicle Year : 2010

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Roopert Mon Dec 30, 2019 5:24 pm

Paul - maybe this has varied with time, but I know that the Cascade (2?) on my 1999 conversion had an outer cover that was made of some form of fibre-filled plastic. I know a bit about its internal makeup because one of my lovely neighbours backed her car into it, breaking it, and drove away without telling me. I repaired it successfully with Araldite, and sprayed it a few years later.
Roopert
Roopert
Member
Member

Male

Posts : 3799
Joined : 2019-03-10
Location : South East
Auto-Sleeper Model : Trooper
Vehicle Year : 2005

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Paulmold Mon Dec 30, 2019 6:10 pm

Roopert wrote:Paul - maybe this has varied with time, but I know that the Cascade (2?) on my 1999 conversion had an outer cover that was made of some form of fibre-filled plastic. I know a bit about its internal makeup because one of my lovely neighbours backed her car into it, breaking it, and drove away without telling me. I repaired it successfully with Araldite, and sprayed it a few years later.
I have one in the garage which I'm sure is cast aluminium but you could well be right. Whatever they are made of, they are extremely fragile and go brittle with age.

_________________
Nice to be important but more important to be nice
Paulmold
Paulmold
Donator
Donator

Male

Posts : 26679
Joined : 2011-02-21
Member Age : 73
Location : North East Wales
Auto-Sleeper Model : Sussex Duo
Vehicle Year : 2010

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by scmarf Tue Dec 31, 2019 6:20 pm

Truma Cascade immersion - PRV replacement Img_4110

This is it. It's pretty manky so not difficult to improve. The surface is pretty rough. I think from the texture of the inside it was quite smooth when new. I think the rough texture should help with adhesion but I would like to make sure with an 'adhesion promoter'. I'll see if I can find some Hycote. The structure underneath this cover looks to be cast aluminium. Maybe there was a misunderstanding somewhere.
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Roopert Tue Dec 31, 2019 6:54 pm

That's pretty much what mine looked like. I think the top (smooth) surface degrades in UV light and drops off, leaving a sort of fibrous finish which is very difficult to clean. I only used Hycote as that was the make that happened to be available - I suspect that any plastic primer will probably be Ok.

IIRC, this is where I bought it - lots cheaper than Halfords, even with shipping included!

https://www.ebay.co.uk/itm/401564954827/
Roopert
Roopert
Member
Member

Male

Posts : 3799
Joined : 2019-03-10
Location : South East
Auto-Sleeper Model : Trooper
Vehicle Year : 2005

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by scmarf Sat Feb 08, 2020 6:48 pm

Truma Cascade immersion - PRV replacement Carver10

This is it after two coats of 'Hycote' plastic primer and 3 coats of the local hardware store's gloss white cellulose. The paint thickness is starting to soften the definition of the logo at this point. The Hycote does recommend using an 'adhesion promoter' so we will see how it stands up to use this summer. A four week tour of Scotland should prove test enough up!. I dismantled it for painting and gave the screws a coat of rust converter and WD40 for good measure. I like to be thorough.  hugegrins.
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by Roopert Sat Feb 08, 2020 6:56 pm

It looks good - definitely worth doing. I'm a bit surprised that you have corrosion on the fixing screws, as I recall that all of mine were stainless - perhaps that's one of the things that was changed during the years of production.
Roopert
Roopert
Member
Member

Male

Posts : 3799
Joined : 2019-03-10
Location : South East
Auto-Sleeper Model : Trooper
Vehicle Year : 2005

Back to top Go down

Truma Cascade immersion - PRV replacement Empty Re: Truma Cascade immersion - PRV replacement

Post by scmarf Sun Feb 09, 2020 12:16 am

Roopert wrote:It looks good - definitely worth doing. I'm a bit surprised that you have corrosion on the fixing screws, as I recall that all of mine were stainless - perhaps that's one of the things that was changed during the years of production.

I refer to the 8 long screws that hold the two parts of the cover together. I dismantled it to get good painting access to the plastic parts and avoid painting the metal parts. The four screws that hold it to the body are indeed stainless. As I say, I like to be thorough hugegrins
scmarf
scmarf
Member
Member

Male

Posts : 59
Joined : 2019-04-01
Location : Lutterworth
Auto-Sleeper Model : Clubman GL
Vehicle Year : 1998

Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum