Help! No hot water!!

[mess1]

Hi,
Hopefully someone can help me with this, central heating pump burnt out over the weekend, had no heating for two days but the hot water worked fine. so i got my spanners out and changed the pump this mornin. the pump valves were seized so had to drain the system to remove the pump. replaced the pump, heating works better than it has done for years, however, the is no hot water!!
The boiler is a Glowworm spacesaver 45-60b (yes, i know it's old!!) The boiler fires up and runs ok for the heating but will not heat the water up!
When the timer (Randall 102) is set for hot water only, the boiler goes out, when it's on hot water and heating it stays on but no hot water
I've tried locating a diverter valve but with no luck.
Any help/ideas would be greatly appreciated

 

[gas4you]

Withe the age of this boiler I would think you have a gravity primary system. Do you have four pipes off the boiler? If so you have.

Could be airlock or blockage in the gravity primaries, or lack of water.

 

[mess1]

Hi Dave,
there are 4 pipes coming off the boiler, how would i sort an airlock or blockage? I'm getting a bit p!**ed off with it now, been scratching my head for hours!!

 

[gas4you]

In your case the pump is only for the ch rads.

Check the F&e tank is full in the loft. If so drain some water from a drain off and check that the f&e is emptying/filling at the same time.

If not you have a blockage in the cold feed where it joins the primary return.

I am assuming you do not have a zone valve on the hw circuit.

The usual way to remove a primary airlock is to remove the boiler stat phial and let it overheat and bang for a minute, but as your boiler is so old I would not recommend this, it could split the heat exchanger.

Try draining and re-filling once you have proved there is no blockage, or back filling via a drain point.

 

[mess1]

the f&e tank is filling correctly, just drained the system and refilled but still not working, the boiler fires up for about a minute then goes off!! To backfill the system, would it work by holding the palm of my hand over a mixer tap, opening the hot water, then the cold? if so, how long would that need to be done for?

 

[Slugbabydotcom]

Is there an air vent near to the flow connection on the cylinder that needs opening?

Airlock is in your primary circuit! Faffing about with mixer taps is not relevant to this problem.

 

[bengasman]

safest way for diy is to start with a backfill. clean the system as soon as it is working again, these ancient setups are alwasy full of sludge

 

[mess1]

Hi,

As far as i can make out, there isn't a vent near the cylinder.
How about if i bled the system from the cylinder hot water return, would that make a difference?
Haven't got a long enough hose to backfill!

 

[Terrywookfit]

Try backfilling or sucking on the vent pipe!!

 

[mess1]

To backfill, do i connect the cold water from the kitchen tap to the CH drain point? If so, i'll need a long hose and a couple of jubilee clips then!
If i try sucking the vent pipe, how will i know when it's clear?

 

[mess1]

I'va admitted defeat, plumber in at 8 in morning.

Thanks for all you help people, much appreciated

 

[mess1]

Quick update... plumber in for 3 hours this morning... 25 years experience, couldn't find out what was wrong with it!!!!
I got home from work, scratched my head for half an hour and started tracing the pipes, starting at the cylinder and working back to the boiler.
Eventually found the problem.. a radiator had been removed from the bathroom and the seperate pipes were capped off under floor level!! Talk about cowboys
Drained the system halfway, put a service valve on each pipe (to have a rad fitted after christmas) filled the system back up, bled all rads, bled the two offending pipes and as i type this, the water is heating up for my first bath in my own house for 3 days
And guess how much the plumber is charging for 3 hours investigation..... a pint when i see him out in town!!