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Afternoon,
Need some plumberly advice please. Switched on the CH for the first time after the summer and our top floor (loft conversion) rads aren’t heating.
Boiler and rads (ground floor) fine, 1st floor rads fine (hot water storage tank there). Top floor cold.
Tried bleeding them and they’re fine. Tried messing with balancing them and still no heat. Heating pump next to the tank is a red Grunfos. Read that this might be clogged but can’t tell if it’s spinning. Does it make an obvious noise when operating properly?
Any help (before we call a plumber in) would be great as new baby arriving in next 3 weeks and my heavily pregnant wife would like it resolved soon!
Thanks, Chris
Does it make an obvious noise when operating properly?
The pump's working (at least a bit) if you've 2 floors of hot radiators and your HW tank heats. They've usually got a 3 position control for pump speed, try cranking that up and see if it helps, and make sure any TRVs on the top floor are open. If they've been closed down for a while the pins can stick but can usually be freed with a bit of careful plier assisted wiggling.
Does it make an obvious noise when operating properly?
IME they make a quiet hiss, like sucking air between your teeth. Most noticeable when they first spin up.
"Does it make an obvious noise when operating properly?"
Be careful, it'll be hot, but you can feel a faint vibration. A screwdriver touching the big screw in the centre will transmit it without the heat (to start with 🙂 )
Is there a separate thermostat/zone valve for the loft?
Thanks all, same thermostat for the whole house.
Three cold rads upstairs but the inlet pipes are cold (ie before the water reaches the TRV) so surely these should be hot regardless of TRV? Bathroom rad is doesn’t have TRV and is still cold.
Pump working (thanks Timba) and on full throttle
Are the rads turned on? So no valves closed upstairs.
Rads and valves all open upstairs
deleted - was rubbish!
Turn on all the radiators on all floors i.e. make sure the first floor ones heat up.
How old is the plumbing? 1960s style was single pipe, a circuit that ran around one floor with pipes to each radiator. If that's how yours is and the loft conversion took a feed off one of the first floor radiators it won't work unless the first floor is on.
If it's a modern flow and return circuit setup this will be bollocks.
In related news, I've just fixed my back boiler which hasn't been working for a couple of months (and I CouldntBA because Summer).
Anyone know where I can buy spares for a 40 year old boiler? (One-pipe system as Murray says.)
Could be an air lock or partial blockage that’s settled in over the summer. Try this:
Ensure heating is on and thermostat demanding heat (just crank it to max)
shut down the TRVs on all the rads on the lower floors (that are currently working)
This will force all the pressure from the pump through the rads upstairs that are currently not working.
If the rads now get hot reopen the trv’s on the lower floors and see if the problems gone for good. If not might just need to balance the system (or you could work around this by ensuring the trvs on lower floors are set just high enough to warm that room so they shut down and start diverting flow upstairs so long as the thermostat is still demanding more heat)
Possible air lock as suggested. Turn off all working rads to force through system. Worked for us when two downstairs ones wouldn't come on after a bleed.
Thanks all. Regards an air lock, do I turn off just the TRVs or the TRVs and the outlet valves also?
Thanks
Thanks Murray, 1960’s ex council so guessing it’s the single pipe option. If the TRVs are off but the outlet valves on, will that work?
I think you should be fine just turning off the TRVs. The lockshield valves on the other side of the rad should have been adjusted to balance the system, so if you do turn them off, count the number of turns so that you can put them back the same.
Hard to tell - if single pipe all the radiators could be in series in which case a shut TRV will stop downstream radiators warming up or the radiators could all be in parallel with the pipe. The loft conversion could be different again.
Best to be systematic and try all TRVs on all floors closed (frost setting), then open one (turn up to max) in the loft and see if it warms up. If it doesn't, start opening one at a time until all open.
My wife forced me to get our house (built 1967 by a local builder) converted to modern flow and return which was horrendous - the first floor is 6'x4' 3/4' ply so all that had to come up, the downstairs is parquet over concrete. We ended up with flow and return on the first floor and dropping pipes for the ground floor with creative routing e.g. living room drops in the garage and behind kitchen units then through the walls.
Good luck!
Forgot to say - despite the hassle and cost of changing to flow and return it was well worth it! House now heats up properly and evenly (before anyone says I should insulate it it's 1960s timber frame so the only way to do properly would be external cladding and I don't have the cash).
One other thing you can do if the radiators are not in series is to turn off the rads that are working to see if you can push water to the cold rads.
Also the pump is not really a pump so to speak more an aid. It can spin and not reall do anything.