Radiators not getting hot enough, pump on constantly-help!

moneysavingplumber

Baxi Bermudas don't usually incorporate pump over-run, so the pump should stop when you switch the CH off at the programmer, even if it does have pump over-run it would stop after eight minutes usually. Check that to make sure it doesn't go off after 8-15 minutes as I can't remember for certain if they have over-run or not.

If the pump is staying on after the heating and hot water are switched off at the programmer then it's usually caused by a faulty microswitch within the motorised valve. Another possible cause would be a frost thermostat although in theory these would also cause the boiler to fire, so i t sounds a little odd.

The poor performance of your system sounds likely to be sludge as several have pointed out. Check the boiler thermostat is also turned up to at least 3 or 4, it is behind the removable fascia panel underneath your fire-front.

gravitytolls

Fran wrote:

It sounds like they might need bleeding. You need a key thing that fits onto one side top of radiator, you need to let any air out until liquid comes out.

You must turn the pump off to do this.

simonhgreen

Thanks to everyone.

i'm going to start by trying the easiest things - the boiler therm was on 1 (the guy servicing did this) so I've turned it up & will see what happens, otherwise I'll try the other suggestions (& probably get wet, dirty and possibly bankrupt).

I had a look at several threads on CH problems and would like to propose the annointment of a new superhero - moneysavingplumber!!!

You obviously know your stuff and you're doing a fine job of counter-balancing the probably unjust public perception of plumbers gained through sensationalist papers/tv programmes, etc.

If you happen to be in the south wales area and looking for clients.......

Thanks again

djohn2002uk

2hrs later and I would have expected another post announcing that turning the boiler stat up had cured the problem, but perhaps he's overcome by the heat....:D
The plumber probably set it on 1 while the weather was ok and only hot water needed but as moneysavingplumber says, this cold weather it needs to be set at 3 or 4. Just moved mine from 3 to 4 yesterday. Fingers crossed for him.

tomstickland

Bleed the system. It took me ages to get all of the air out of the heating system in the house I used to share with the GF.

djohn2002uk

As posted above, air has nothing to do with it. If the rads had air in them they would be cold at the top, not the bottom.
All the bleeding in the world wont cure rads that are warm at the top only.

simonhgreen

Hi djohn2002uk & all

It looks like it was the boiler stat & the rad is definitely a lot hotter now.

Early this morning I was thinking I was looking at squillions on a new system, now I'm happy and getting warmer.

Thanks for all your help guys, it's great to have a site that is genuinely run for the good of all.

Cheers!

tomstickland

You've reminded me now. Whe I was fiddling around the central heating I found the 0-6 setting knob on the boiler and whacked that up to make it run hotter.

PS: have you tried bleeding the system?

moneysavingplumber

djohn2002uk wrote:

2hrs later and I would have expected another post announcing that turning the boiler stat up had cured the problem, but perhaps he's overcome by the heat....:D
The plumber probably set it on 1 while the weather was ok and only hot water needed but as moneysavingplumber says, this cold weather it needs to be set at 3 or 4. Just moved mine from 3 to 4 yesterday. Fingers crossed for him.

The boiler stat should be at a mid to high setting anyway if it sized correctly for the property and an auto bypass is fitted, regardless of the time of year. It should really be set up when the system is balanced to give the correct temperature on the flow immediately next to the boiler, and the temperature drop between the two would be eleven degrees for a conventional boiler and twenty on a condensing. There shouldn't be any need for seasonal adjustment on a modern fully-pumped system.

wizzer

moneysavingplumber wrote:

The boiler stat should be at a mid to high setting anyway if it sized correctly for the property and an auto bypass is fitted, regardless of the time of year. It should really be set up when the system is balanced to give the correct temperature on the flow immediately next to the boiler, and the temperature drop between the two would be eleven degrees for a conventional boiler and twenty on a condensing. There shouldn't be any need for seasonal adjustment on a modern fully-pumped system.

So, I've just had a Glow worm 24hxi installed which has a max setting of approx 82C.

If I set my cylinder temp to 55C (recommended hw temp?) then the boiler will need to be set to 75C to avoid boiler over-run? I ask because I have had problems with a continuously running pump possibly because the boiler thermostat has not been set high enough?

Thanks