Stone cold radiators downstairs, hot upstairs.

KazDub

We have gas central heating. For some time now the radiators downstairs have stopped working. They've been bled, but very little air came out. The radiators upstairs work fine and the water tank gets heated also.
An unusual thing is that after two to three hours the heating just seems to shut itself down. The boiler appears switched off, the radiators upstairs cool down but we haven't actually switched the heating off. We've resorted to plug in radiators downstairs until we get someone in to work on this but as we're both at work during the week and have things on over the course of a few weekends we haven't had a chance to get someone out. The place is like a mortuary in the evenings!
Has anyone encountered a similar problem and should I expect a hefty bill?

dpofloinn

There are a lot of variables that could be at play here.

First off what kind of controls have you got on the system ie:Time clock,motorized zone valves,room stats,T.R.Vs etc

KazDub

OK, excuse my complete and utter ignorance of all things plumbing/heating related. I'll answer what I can:

For time clocks: We have the timer that's part of the Minuet boiler and also one that we added ourselves to the hot tank. The timer on the boiler isn't in use at the moment, when we turn the heat on we do so using the non-timer option.
Motorized zone valves: I don't know what they are or if we have them.
Room stats: Not sure if this is what you mean, but we have thermostats upstairs and downstairs, I can't be exact but they're both set to around the 20 degrees mark.
TRVs: Nope, nada...not a clue what they are.

Sorry!

mloc123

Sounds like your water pump is not working, warm water will rise naturally and heat the upstairs but without the pump downstairs will not.

dpofloinn

Your grand I should have really described what these items are

Motorized zone valves: Electronically controlled valve that opens and closes heating to different areas as required eg: Upstairs Downstairs, Hot water cylinder
T.R.V:radiator valve with a big plastic head that has settings from 0 to 5 written on it
Room stat:is just another name for the thermostats that you have

As for the downstairs rads not heating the likely hood is you have motorized zone valve which has stuck in the closed position or your stats may be sticking giving a false readings

Having said all that it is very difficult to give a proper diagnosis without seeing your heating set up but I hope this can help you in some way

KazDub

Ah, ok. We don't have TRVs, just the old fashioned clockwise / anti clockwise for on or off.
In the hotpress we have two large white 'boxes' which have lights that turn on when the heat is on. I'm wondering if these are the zone valves you're talking about. Would it be worth us having a closer peek at these?

dpofloinn

YES they could very well be mzvs are they attached to the pipework? they are probably for the upstairs circuit and hot water the downstairs circuit mzv will most likely be near the boiler see if you can find it then see if it activates when downstairs heat is called for also check and see if you adjust the downstairs thermostat does it activate the downstairs rads

KazDub

Yes, they're attached to the pipework and only seem to activate when the heating's turned on. I'll get the hubby to have a look tonight and see if we can work out if one of them is acting up.
Thanks for the help!

sanbrafyffe

just to let you know these can be operated manually

KazDub wrote: »

Yes, they're attached to the pipework and only seem to activate when the heating's turned on. I'll get the hubby to have a look tonight and see if we can work out if one of them is acting up.
Thanks for the help!