Vaillant EcoTec Plus 937 Hot Water

[Purplepengiun]

My vaillant ecotec plus 937 only delivers about 2 minutes of hot water before it runs cold.

Domestic & General sent their plumber out who said it was sludge in the domestic hot water heat exchanger (blockages not covered under the policy so couldn't fix it). I had the system flushed and the dhw heat exchanger replaced. No improvement. Same problem.

The D&G plumber came back and said the problem must be to do with the unvented water storage tank (unvented hot water tank excluded under the policy so couldn't fix it).

I rang a CH Engineer who said that it was probably the main heat exchanger rather than the water tank, and due to the cost of repair, is likely to be write-off of the boiler, so best to get a new one. As it was installed in 2009, I am reluctant to give up on it just yet.

As you can appreciate I am confused as to the way forward. I just ran the bath hot water tap for 5 minutes. The boiler fired up with flames visible in the main heat exchanger after 5 minutes, but water in tap was running cold at the same time. Status code was S24. On a previous occassion when I tried this, the main heat exchanger flame did not stay on long and the status code cycled between S20 and S28

Does anyone have any ideas?

 

[muggles]

And thus we discover the problem with paying into boiler insurance policies...you'd be better off putting the money in the bank.

As for the problem with your boiler, it sounds like it's not firing at full rate, nor is it charging the hot water tank. As there are no error codes it's hard to say what the exact problem is without being in front of it. You need either an independent Vaillant specialist or even Vaillant themselves. I'd advise an independent first - a good one should at least be able to diagnose and advise whether it's going to be cheaper for them or Vaillant to sort it

There are known faults on early versions of this boiler model...dodgy PCBs and shunt pumps amongst other things

 

[Bunnyman]

With this model unless u got a good local engineer go for the vaillant fixed price repair, around £250 but whatever it is they will fix it

 

[Tipper]

With this model unless u got a good local engineer go for the vaillant fixed price repair, around £250 but whatever it is they will fix it

I agree. We had hot water flow problems with our 937 which were caused by the outlet pipe within the storage cylinders collapsing when water was drawn. (Due to out soft water we think)
Our excellent local guy decided it would take him too long to replace the pipe and it would cost a lot of time and hence money and as Vaillant would guarantee to fix it and do anything else required at the same time he recommended going for the Vaillant fixed price repair.

Whilst it seemed expensive at the time we did get the guaranteed repair and some other parts replaced at the same time.