Boiler/Heating help please

sancho

Hi there, I fully expect this post to be massive, and not enough of the required detail. So I will apologise in advance and will strive to provide further information where needed.

My house is freezing. The heating has been on since 3 o'clock this afternoon, with the thermostat set to 21 degrees. As a sort of experiment the thermostat has been on 30 for an hour or so, with all radiators set to max.

I have a back boiler with 7 radiators (3 bed semi - built about 1950) all except 1 radiator have TRVs fitted (the one in the hall, where the room stat is, doesn't)

My, albeit limited, knowledge of heating systems are that (when the heating is 'on') you turn the room thermostat to the required temperature, if it is below that temperature it will tell the boiler to come on, heat the water and pump it around the radiators, heating the rooms up. When it reaches the required temperature it tells the boiler to stop heating, and so on and so on.

Therefore, when you turn the thermostat, when it 'clicks' that is roughly the current temperature, within a tolerance obviously. Mine is clicking at the moment at around 12 degrees. A thermometer in the kitchen tells me it is 10 degrees in there, and one in my baby daughter's room tells me it is 14 degrees.

Obviously being a back boiler we can hear it 'click' on and fire up when we are in the front room. As i'm sat typing this I can hear it come on, run for a few minutes, and then go off. 5 mins or so later it will click on. Repeating that seemingly endlessly

Bearing in mind the heating has been on for 3 hours, 1 of which all of the thermostats have been on max why is it still so cold!!!

On a side note, which I'm sure is probably something to do with it, every so often in the evening (after the heating is 'off') the boiler will kick in, and you can hear the pump working water around the system. The way to turn it off is to press a valve on the top of the blue box in the picture below, which seems to 'unstick' something and turn it off. I have no idea what the blue thing is, or what it does, but it seems to stop the boiler working when it shouldn't be. (it's the bottom one we press, presume the top one is for hot water? - Which we have plenty of!!)



Again, sorry for the long post, and am planning on ringing plumber this week, but don't want to get either ripped off or blinded by silence when he turns up. Any advice would be great

macman

Make and model of the boiler would help.
But sounds like a problem with the 3 port valve sticking, you shouldn't have to 'unstick' it at all-it's supposed to be fully automatic. If it's sticking on the DHW setting then hot water canot pass to the CH circuit. Does it respond when you turn the tank 'stat up and down (should be on 60C minimum setting). Turn it up full and the valve should respond as the stat calls for heat. Turn it down and the valve should move the other way.
Or could just be a sticking pump-have you checked that?

sancho

Thanks, when the heating comes on the blue thing whirs like the motor is working, I took it off (it just unclips) and all it seems to do is turn something a quarter turn, presumably from off to on and back again. Is the pipe behind it the zone valve?

Just seems odd that there's some heat, the radiators are on, just don't seem to be heating the house, although I've just gone in the spare bedroom and It's hot in there?

sancho

macman wrote: »

Make and model of the boiler would help.
But sounds like a problem with the 3 port valve sticking, you shouldn't have to 'unstick' it at all-it's supposed to be fully automatic. If it's sticking on the DHW setting then hot water canot pass to the CH circuit. Does it respond when you turn the tank 'stat up and down (should be on 60C minimum setting). Turn it up full and the valve should respond as the stat calls for heat. Turn it down and the valve should move the other way.
Or could just be a sticking pump-have you checked that?

Will hunt out the model of the boiler

How do I check if It's the pump sticking? Thank you also

macman

sancho wrote: »

Thanks, when the heating comes on the blue thing whirs like the motor is working, I took it off (it just unclips) and all it seems to do is turn something a quarter turn, presumably from off to on and back again. Is the pipe behind it the zone valve?

Just seems odd that there's some heat, the radiators are on, just don't seem to be heating the house, although I've just gone in the spare bedroom and It's hot in there?

Well if the boiler is cutting in and out every five minutes, it's only providing CH for half the time, so it's not surprising in this weather that the house will not come up to the required temp.
If there are zone controls on the system, then it would be normal temp in the rooms not affected by the faulty zone valve.
You can turn the pump impeller by rotating the shaft with a screwdriver to see if it is free, there should also be a speed control, try turning it up one notch.

Canucklehead

Hi

Valves are motor open, spring return.

BG badged Acl Draytons.

The black lever at the top of the blue head will manually open the valve.
If the cylinder stat and room stat are calling for heat then these levers will move across and drop into a recess.
If not then manually move it to lock it open.

Any c/h now?

GSR

sancho

Thanks again. Curse me for trying to get another winter out of it before getting it fixed!!

When the heating is on, and CH is called for the black lever goes down and locks. but is not heating the house properly. When the heating is off it 'unclips' and raises, no heating. As mentioned above it occasionally sticks down when the heating is off - fiddling with the black lever will make it return up and the heating stops (as it should)

At the moment the lever is down, but the heating still isn't hot. So does that mean the motor is working (the lever is where it should be) but there is something wrong with the valve it is, (or isn't!) moving behind it?

I don't really understand the zone thing, any chance of a Simpletons explanation?

The pump has options for I, II or III. Presuming 3 is the highest, which is what it is on

Canucklehead

Hi

Is the pump above the valves and pipework shown in the photo?

GSR.

sancho

Presume the pump is the red and black thing above it?

Canucklehead

Hi

Slacken the silver screw in the middle and water should drip out.
Remove it completely and inside is the impeller shaft.
If the pump is running you'll feel it with the tip of a finger. (careful you'll wear your finger down.)

My suspicion is the system is drying out. It would be worth checking the expansion tank in the loft to see if it's full.

The third speed is a bit OTT for these systems IMO.



GSR.

sancho

I did start to remove the screw, but water came out so I quickly put it back in! But it's ok to remove? Will it take my finger off?

Will have a quick look in the loft