Indirect Unvented cylinder, Combi Boiler and Nest Thermostat

[Chris1012]

So many posts on here now, hard to keep up and on topic.
Does this mean it should or should not take 40seconds to get hot water from the taps?

 

[Bibbs118]

Something that is always over looked on these installs is if the dhw draw off from the combi is to a frequency used hot tap, the boiler sits in anti cycle for 5 mins every time the flow turbine moves, meaning it can take hours to heat the cylinder.

 

[Chris1012]

As requested, Pictures from the cylinder. Seems the hot feed from the top of the cylinder is branched off - 1. Specifically to the upstairs bathrooms x 2 (1st floor and loft).
2. The rest of the house

 

[Best]

Who lagged the discharge pipes?
Also I would get that plastic push fit stopend replaced with a brass compression stopend

 

[Chester]

Ew, polyplumb

 

[Welder]

Wonder if they wore a wool shirt too... Who the hell puts that rubbish on. Especially in a cold space like a basement...

 

[Scott_D]

Any pictures of under the boiler, 2 port valves etc around the cylinder

It is insulated, not they way most would do it but I don't think it specifies anywhere what standard if insulation must be used?

 

[Welder]

It's about appropriateness. If that space get s down around freezing then it needs better protection.
If however it's to protect against rodents, then that works brilliantly as they don't like the fibrous nature of it and leave it alone... Instead they use the polyplumb elbows to sharpen their teeth

 

[Chris1012]

Any pictures of under the boiler, 2 port valves etc around the cylinder

It is insulated, not they way most would do it but I don't think it specifies anywhere what standard if insulation must be used?

Unfortunately not, as the pipes from the cylinder are all under the panel that has been fixed back to the cupboard.

The location of the boiler is within the kitchen.

I believe there is a 3 port valve, 2 of the ports are for underfloor heating within the kitchen/diner area.

 

[Chris1012]

It's about appropriateness. If that space get s down around freezing then it needs better protection.
If however it's to protect against rodents, then that works brilliantly as they don't like the fibrous nature of it and leave it alone... Instead they use the polyplumb elbows to sharpen their teeth

Never gets below around 15 degrees

 

[Best]

I am surprised if MIs state just 28 minutes for that cylinder reheat.??? I would have thought it is much more.
The hot water outlet on unvented cylinders I prefer to drop the pipe before ever raising the pipe to a higher level. Just raising a hot outlet will mean some of the stored heat from the cylinder will keep heating the water in the raised pipe, therefore wasting energy.

 

[ShaunCorbs]

I am surprised if MIs state just 28 minutes for that cylinder reheat.??? I would have thought it is much more.
The hot water outlet on unvented cylinders I prefer to drop the pipe before ever raising the pipe to a higher level. Just raising a hot outlet will mean some of the stored heat from the cylinder will keep heating the water in the raised pipe, therefore wasting energy.

20kw going into the coil will re heat in around 30 mins

 

[Best]

20kw going into the coil will re heat in around 30 mins

I am going to check the MIs on Telfords.
I thought they claimed it to be much longer.

 

[Chris1012]

From the Telford user manual

 

[ShaunCorbs]

That's the direct on have a look at the indirect spec

 

[Best]

35 minutes for full reheat, is what I read on 250l indirect.
Not bad, if that's correct.
I have one installed isn't achieving that

 

[ShaunCorbs]

35 minutes for full reheat, is what I read on 250l indirect.
Not bad, if that's correct.
I have one installed isn't achieving that

Size of boiler ?

 

[Chris1012]

That's the direct on have a look at the indirect spec

That was indirect. My cylinder is 250l

 

[Best]

Size of boiler ?

30kw WB gas boiler. It is my partners house, so something I am aware of. Pipework all mine, except the gas, so no bother there.
I need to investigate it more.

 

[Best]

That was indirect. My cylinder is 250l

View attachment 33580

Yes, I got same on searching. 35min from cold to 60 degrees

 

[ShaunCorbs]

30kw WB gas boiler. It is my partners house, so something I am aware of. Pipework all mine, except the gas, so no bother there.
I need to investigate it more.

Yea should be able to heat that no problem

 

[Welder]

What flow temp is that at tho?
I've just installed twin 150L OSOs and they state recovery rates at 80 degs flow!! Still, makes it look good

 

[Chris1012]

What flow temp is that at tho?
I've just installed twin 150L OSOs and they state recovery rates at 80 degs flow!! Still, makes it look good

How can the flow rate be confirmed/checked?
The cylinders temp is around 65c

 

[Welder]

Its the boiler flow temp that OSO quote at 80 degs. Most boilers closer to 70 so recovery rate way longer than stated depending on coil design (ability to transfer heat).

 

[Chris1012]

Its the boiler flow temp that OSO quote at 80 degs. Most boilers closer to 70 so recovery rate way longer than stated depending on coil design (ability to transfer heat).

apologies for my ignorance, I am not technical at all.
My understanding was once the cylinder is heated up, the outlets would draw the hot water from the cylinder and not the boiler anymore...?