No Hot Water

[Stusmk1]

Hi All

Common problem but can't find a solution on other threads. I'm new to this so go easy on me.
I am not getting any water through the hot taps at all. When turning on the water heater it starts up but turns straight off. It has a full bottle of gas, it ignites but doesn't stay lit. I've replaced the burner unit but no change. It is a Carver water heater.
Any help will be gratefully received

 

[IanB1485]

The last carver I had to look at had a similar fault , it was on a motorhome with an internal tank. Symptoms :- turn on hot water tap , funny gurgling noise , no water, Activated Carver , control panel goes green , and then goes into error. Fault :- water tank had become detached ( the tank is held onto the body with a large nut and washer , which connects to a long internal shaft) the end of the shaft had snapped , presumably through freezing ( the owner didn't know he had to drain down the system in winter) Sent the unit away to a guy who repairs them, not cheap.

 

[Stusmk1]

The last carver I had to look at had a similar fault , it was on a motorhome with an internal tank. Symptoms :- turn on hot water tap , funny gurgling noise , no water, Activated Carver , control panel goes green , and then goes into error. Fault :- water tank had become detached ( the tank is held onto the body with a large nut and washer , which connects to a long internal shaft) the end of the shaft had snapped , presumably through freezing ( the owner didn't know he had to drain down the system in winter) Sent the unit away to a guy who repairs them, not cheap.

Hi IanB1485

Thanks for the quick response. That's not great news then. I'll start having a look for repaired units or someone to repair it.

Thanks for your help

 

[Andy Norfolk]

I don't have any knowledge of the unit your talking about. But does the hot water tank have a drain valve that has been left open? It would mean the tank has no water. I know this as I did it myself 😂 on our Alde system.

 

[Hutch]

Just a throw in, do you have to remove the cover for the intake / exhaust for the Unit. That stops the unit from running.

 

[ProfJohnL]

First of all the appliance you have will be at least 25 years old. Spares are getting harder to find these days.

The burner control module (BCM) is responding to a demand for heat, and tries to ignite the gas, If the flame sensing probe is unable to receive the flames signal the BCM continues to fire the ignitor for about 10 seconds before locking out, with a red LED on the control panel.

As you have already changed the BCM I assume for a remanufactured one, we can eliminate blocked burner bar, and flame probe position,

That tends to leave low gas supply pressure. or perhaps missing parts in the flue cowl assembly


If you look at this diagram you can see the BCM, to the left of it there is a cast metal flue cowl (#4) and a larger flat metal plate with some high temperature ceramic matting (#16) and of course the DMC exterior cowl. Theses must be fitted to enclose the burner fin pack. Without them the flame will be unstable which might be causing your problems.

Another possibility is the caravans gas supply may have been contaminated with an oily substance which tended to collect the the lowest points in the gas installation like the cascades inlet coupling. This might be restricting the gas flow.

All work on gas appliances and installations in the UK must be carried out and tested in accordance with the ACOP and standards. I suggest you contact an Approved Workshop Scheme engineer to investigate and repair or replace the applaince.

 

[IanB1485]

A touring caravan is exempt of the Gas safe regulations so a mobile engineer from the MCEA group who will have the necessary qualification to work on the unit can work on the gas systems . Back to the one I attended, the drain down unit it was just a blanking plug underneath the motorhome , not the easiest to access ! Hopefully your drain down valve will be the internal type with a yellow lever , vertical equals drain , horizontal equals system will fill