Seized pump?

[AliG]

So the 4 port mixer is gargling horribly and the flow meters bounce up and down. It seems to be knackered.

 

I will get out the installer to have a look and probably replace the valve.

[dpmiller]

sounds like there's air in the system, tbh.

[AliG]

 

20 minutes ago, dpmiller said:

sounds like there's air in the system, tbh.

It does but I don't think it would affect the operation of the mixer valve.

 

I have noticed that the system is quite noisy in the morning when it comes on. This has only been for the last few weeks, before that there was very little noise.

 

This again makes me wonder if it had something to do with the boiler being serviced, although I wouldn't have thought that anything would happen there to allow air into the system.

 

If there is air in the system it seems to be in the loops between the manifolds and the boiler.

 

I wasn't here when it was all installed. This time I can be around and ask how to bleed it and so on. It seems a lot less straight forward than a radiator based system.

Edited November 5, 2020 by AliG

[AliG]

Annoyingly I can usually look after something if I know how it works but despite numerous requests no one would talk me through the heating system and anything I had to do maintenance wise.

 

There is a low loss header in the plant room. This is the only place anywhere on the system I can see a pressure garage and it is reading basically 0. Does this suggest that the system needs to be repressurised or am I misunderstanding it?

 

 

Edited November 5, 2020 by AliG

[AliG]

Looks like this was the issue.

 

Broight pressure up to 1.3 bar. Water flowing and a lot less noise.

 

I specifically showed the guy who did the boiler service the UVC, heater etc if he wanted to check them all out and he didn’t seem interested at all.

 

Anyway now I know it needs to be repressurised and how to do it.

 

Funnily enough in my last house no one showed me how to do it either and I had to figure it out for myself.

[SteamyTea]

It may be worth you doing a sketch of your system, bit like a London Underground map (topological).

Probably all become clear how it works then.

 

[AliG]

Success, all working now. Checked all of the manifolds they seem good. No more weird noises and flow restored.

 

25 minutes ago, SteamyTea said:

It may be worth you doing a sketch of your system, bit like a London Underground map (topological).

Probably all become clear how it works then.

 

 

I do have the original drawings, but they don't mention what different items do and how you should set them up. In some cases I think they don't want people messing around with the system, but a lot of it is quite simple once you know how it works. I always worry that my wife would have no idea how these things work if I wasn't around and have to constantly get people in. Not that she couldn't figure them out, she just isn't interested.

 

The things I have learned that I think I should have been informed of.

 

1. The end valves on the manifolds are automatic air bleed valves - I had guessed this but wasn't sure. Some of them were closed.

2. The pressure on the low loss header has to be periodically checked and topped up. The taps to top it up were fairly obvious, but only because it looked like my old system. I surely should have been told this. As I said no one told us in our last house either, we also stayed in an Airbnb where the boiler kept tripping out and I eventually figured out it was due to low pressure in the system and fixed it.

3. The things that look like temperature probes on the manifolds are exactly that and if you turn the flow temperature above 48C they will cut off the power to the pump.

 

I am going to label the low loss header for topping it up.

 

Now we are heating with gas!

Edited November 5, 2020 by AliG

[Nickfromwales]

22 hours ago, AliG said:

I surely should have been told this

100%. All sealed systems will eventually lose this head of pressure so topping up is a part of the end users basic maintenance regime. 
FYI, that pressure is not just the pressure in the low loss header. It is one huge unified body of water so that gauge value is representative of the entire system pressure. 
When there is zero at ground level, you’ll have a deficit on any levels above. The risk there is, that air will be sucked in through the air vents you mention ( they operate in both direction unfortunately ) and the the UFH manifolds will start to take in air and send it around the loops. 
Due to the minuscule flow rates in each UFH loop, getting that air out usually requires a purge with cold mains pressure to ‘blast’ all the air out and replace with all water. 
Check for acceptable heat output throughout the floor serviced by the upper manifold to check this has not happened and that you caught it in time. Air locked loops will run cold as there will be no flow on that loop if so. 

[PeterW]

Odd that the LLh is at zero. Did the plumber check the expansion vessel in the boiler ..? Or is it a separate one ..??

[AliG]

Thanks @Nickfromwales I got an email back from the installer and he said it was very odd for the pressure to go to 0 and it was probably something the guy did when he serviced it.

 

He asked me to watch it, but it seems to be holding now.

 

The whole thing started because I thought my daughter's room tended not to heat up as fast as other rooms. The flow was set at 38C there, but that was only giving a floor temp of around 22C which heated the room up very slowly. There is a floating wooden floor in the room with a thin foam underlay.

 

I turned up the flow to 42C and not only did the room heat up faster last night, but the floor was holding more heat and so it didn't seem to cool down as quickly.

 

I got the FLIR camera out and most of the floors in the house seem to run around 24/25C when the UFH is on, so I think her room was set a little low, it is now warming to a similar level. I discovered previously when trying to maximise the efficiency of the heating that the best thing to do was to have as many rooms warming at the same time, so even if there was a room you might not be in until later in the day, just heat them up in the morning with the rest of the house so the boiler doesn't run for as long a period. Thus often her room was taking way longer than others to heat up and the boiler would be running just for that one room.

 

When I did check the floor with the FLIR camera the loops were clearly warming up, but as you got to the middle of the room they were 2C colder, I am not sure if that is just the water cooling as it goes through the loop or their could be some air in the loop. I will give it a while and check again.

[AliG]

5 minutes ago, PeterW said:

Odd that the LLh is at zero. Did the plumber check the expansion vessel in the boiler ..? Or is it a separate one ..??

It is a separate expansion vessel.

 

I am almost certain he let the pressure out when servicing the boiler and forgot to top it up. Thinking back, the weird noises from the heating started a few weeks ago after the service. No sign of it falling since I topped it up yesterday, but I will keep an eye on it in case it is something else.