Toasty radiators but no hot water!

[TheRunningMan]

Hi folks.

For the past few days I've had no hot water (lukewarm) but the radiators seem to be working fine.

It's a condensing boiler, a BG 330+ (Glow Worm) to be exact.

Any advice on where to start would be great. Cheers folks

 

[45yearsagasman]

Thats a heat only boiler so I guess you might have something like these:- View media item 30391 View media item 38425

 

[TheRunningMan]

Thats a heat only boiler so I guess you might have something like these:- View media item 30391 View media item 38425

That is correct yes. I have two that run in-line with each other.

 

[45yearsagasman]

It is most likely a fault with the 2 port valve that connects to the cylinder. Either the motor has failed or it has seized. A test meter is handy in these cases to determine if the valve is actually getting a signal from the programmer and cylinder stat.

 

[TheRunningMan]

It is most likely a fault with the 2 port valve that connects to the cylinder. Either the motor has failed or it has seized. A test meter is handy in these cases to determine if the valve is actually getting a signal from the programmer and cylinder stat.

How will I know which one is the two port valve? Will it be the one closest to the length of pipe that enters the cylinder at the side about 1' from the top?

 

[ianmcd]

They are both two port valves one feeds the radiators the other feeds the hot water, either follow the pipes or put both on at the same time and the one that doesnt get hot at the outlet is the faulty one

 

[TheRunningMan]

They are both two port valves one feeds the radiators the other feeds the hot water, either follow the pipes or put both on at the same time and the one that doesn't get hot at the outlet is the faulty one

Ah right I think I get it now. The valves will only let the water travel one way. Is that right? In between the two valves is a T Junction so the one that comes from the T junction to the valve and then onto the cylinder will be the one for the hot water?

I guess to replace it I would have to drain down the CH system?

 

[TheRunningMan]

Would you suggest any of these in particular?

http://www.screwfix.com/search.do;j...0MwLRQd9yf!-1389567939?fh_search=2+port+valve

 

[ianmcd]

To be honest they all do exactly the same thing some are more reliable than others but it may just be the synchron motor that has gone in the faulty valve , an easy replacement and only costs less than £20 and is a lot easier to replace than the complete valve

 

[TheRunningMan]

Also if I change the lever from 'AUTO' to 'MAN OPEN' will this solve the problem in the short term and are there any risks associated with doing this?

 

[ianmcd]

yes as a temp fix and will heat the CH as long as the hw is calling for heat at the same time and no it wont damage anything

 

[TheRunningMan]

yes as a temp fix and will heat the CH as long as the hw is calling for heat at the same time and no it wont damage anything

Awesome news

£13.49 for a new Drayton Synchronous Motor from Screwfix so a lot cheaper and seems rather easy to swap.

I'll check it out tomorrow if it gets hot/cold when it's running and then take it from there.

Cheers for the help ianmcd

 

[ianmcd]

if you have an electrical mulitimeter check that you are getting 230V AV between the blue and brown of the Motorised valve and if the valve is not opening then it is the Synchron motor, please be carefull though as the valve still has a permanent live supply whether the heating is switched on or not, please make sure you isolate the complete heating supply before attempting to replace the motor, it is an easy replacement to a competent DIYr

 

[TheRunningMan]

Cheers for that. I was going to isolate the whole heating system to be on the safe side. I don't have a multimeter but its been suggested to use one a few times now so I may as well invest in one

 

[TheRunningMan]

The pipe going from the valve to the cylinder was roasting this morning when I got up but the water was still lukewarm. I changed the override switch to manual and still the water failed to heat.

As the pipe going from the valve to the cylinder is roasting, i guess it's not a fault with the valve.

Any other suggestions on what it could be?

Cheers