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The pump is in the hot water cupboard upstairs and I’m pretty sure it is higher than the bleed point on the rads.

Clicked the button on the wilo. It made some different sounds for the duration (the display said it was doing the auto bleed). Eventually I stopped it after 15 minutes. Did it a couple times. no automatic air vents on the system as far as I know

One more question for anyone. when you bleed a non automatic pump you do it until you get water coming through. when I used the auto bleed function on the wilo I didn’t at any point have water come out and the bleeding then stop. Should there be water coming out at the point it successfully bleeds all the air out ?

Thanks for the replies Nick. so you don’t think there is anything obviously structurally wrong with the pipe work?

There is very little pipe work to see. Gas enters from the bottoms and flow and return on top.

Do you mean a drain point on a low radiator?

Boiler probably replaced 10 years ago, old leaky rads replaced for new less than two years ago, no real issue since last week

1.Yes I did open them. 2. auto bleed button pressed and on for a while 3. Well, I’m not sure how to answer that so I guess no. I didn’t test that when I had the pump off, maybe I should have. But the isolators seemed to twist shut and open nicely.

Glad my pump woes are generating such a lively conversation! good news - managed to swap over the pump fine. No leaky isolators, all went well. Thanks chaps. bad news - similar problem, boiler fires up on demand and quickly gets too hot on flow pipe and my boiler (Vailant ecotec plus 415) comes up with F72 error (flow and/or return NTC fault). Ran the auto bleed function on the WILO for 15 minutes, tried with the circuit isolators (silver boxes - don’t know actual name!) manually opened, same result. Pump seems to be running fine just no flow from the boiler. Spoke to Vailant and their technical support said the F72 error meant the problem was external to the boiler. Spoke to plumber (too busy to come out but happy to do a video call while I was trying to get it working) and he said most likely an airlock or maybe sludge build up (though most of the rads were changed a few years back). Spoke to the gas safety check people (who came on Monday for the yearly checkup and reckoned it was most likely the pump) and they have suggested draining, changing a bit of pipe work (more below), filling with cleaner and circulating for a couple days, drain again and fill with inhibitor. the pipe work that they thought needed changing I presume is the ‘u’ section you can just make out in the pics (close up on second pic) on the return pipe work next to the boiler. He reckoned that was an airlock liability and I presume the plan would be to run a ‘t’ straight across to the main return pipe from the down pipe and getting rid of the ‘u’ does that sound like a reasonable plan? Pics in next post

Just seen this. Ok I will do. Does that still influence whether the boiler will work for the heating if there is no call for hot water?

Thanks for the quick response Nick. I’m not a plumbing expert but I think it’s a gravity system! The boiler does heating and feeds the hot water tank and there are a couple of tanks in the loft. im a bit worried about how well the isolators will work as I know there’s already an old isolator in the hot water cupboard that doesn’t turn! So im a little reluctant to have a go myself in case I can’t get the new one to fit properly. But it would be cheaper than getting someone in to do it!

Can anyone recommend a suitable pump replacement for this one? well, I’m assuming it’s the pump as the boiler is working but the heat never gets far from the boiler at all and the pump is making non standard noises!

Not sure my view will be the most popular here but I’m not convinced any SE will provide any useful input that can replace common sense. It doesn’t look too bad to me and it seems that were it actually be continuing to move apart that you would know about it. If the area with the major crack were repointed properly I think it would not be especially obvious that there had been movement. If it were mine I were I would just get some heavy duty ties embedded in the wall and make good. If you wanted to go a bit further you could also take out some stone and fit a large precast concrete lintel into the wall to help join each side of the crack. just my 2 cents!

Don’t much about fan coil units and ashp. my first thought is 16kw sounds way too big if you are already doing a full thermal/air tightness upgrade. how large is the property?

It’s a pretty big lintel for a small fireplace. It’s a bit weird to see that crack - is there more up above in the brickwork (can’t see any from the photo)? Doesn’t appear to be any deflection in the lintel. My instinct is that it should be fine. but it isn’t too big a job to replace since you are back to brick at the moment.

I think you have to be careful with old solid walls that you don’t risk interstitial condensation if you use too much insulation. I generally just used 80mm boards with normal lime render for the finish and levelling coats. Didn’t have any problems with building control but then I was going over building control specs for roof and under floor insulation as well.

I went with the basic Steico and it has worked well. non tongue and groove but foam filled any gaps why diathonite plaster? Can’t you just use slightly thicker wood fibre? Cheaper for same result. i just used nhl lime and sand for the internal render.

I did mine with a capable digger driver friend. Excavated the hole, put a dry mix, level concrete pad at the bottom. tank in. Digger man did an excellent job of mixing up the dry mix in the dumper using the digger bucket. Hose speed was fine for the speed the concrete that went around the stp.

Whole wall will be neatest

Good way to keep anyone who has responded on your side! have you ever installed Ufh?

How hot do you want your house? in my experience the thermostat level needed for a house with Ufh is less than one with radiators.

I just used lime.

Really? I mean it depends on the house. And also on how much you value the aesthetic value of the old construction - a new version is going to be different and not always in a good way.