Advice needed. Issues with underfloor heating and hot water system for new build

[Carrera]

Sorry haven't been able to test much at all, as the system is not really working as it was left for the holidays. At the moment just about able to get warm water, boiler going on and off very 2 mins and the heating was working with a light load, but has now started doing the same. Will have to wait for the plumber to come back next week before I can really try anything

 

[diamondgas]

Give Worcester a call, your boiler is under warranty with them. You may have a fault on the boiler?

 

[Carrera]

Give Worcester a call, your boiler is under warranty with them. You may have a fault on the boiler?

For the hot water, basically boiler fires, flow temp rises (set to 70), modulates lower and lower and kicks off when it goes over 70, water circulates for a couple of mins and then when temp hits about 40 boiler fires again, slowly getting to 70, before we go back round the loop. As you can imagine water takes ages to warm up this way, so have been combining thus with the emmersion over the holidays. I will give wb a call on Monday.

does not do this on heat, gets to 70 and stays there, however this morning started doing above with heating, but after a few attempts of me stopping and starting the heat, it appears to be ok.

 

[diamondgas]

For the hot water, basically boiler fires, flow temp rises (set to 70), modulates lower and lower and kicks off when it goes over 70, water circulates for a couple of mins and then when temp hits about 40 boiler fires again, slowly getting to 70, before we go back round the loop. As you can imagine water takes ages to warm up this way, so have been combining thus with the emmersion over the holidays. I will give wb a call on Monday.

does not do this on heat, gets to 70 and stays there, however this morning started doing above with heating, but after a few attempts of me stopping and starting the heat, it appears to be ok.

Without seeing what's going on it's difficult to give you anything accurate to be honest Carrera! Are you able to get a reading on the return as the flow is heating? If so there should be around 20DegC difference, thereabouts. If there's a rapid rise in temp to 70 before dropping back to 40 then I'd be wanting to know how well the pump was performing and/or is there a potential flow restriction somewhere? If the rise is gradual and there's a maintained 11-22DegC difference between F&R then Circulation is okay IMHO

 

[Howsie]

This one really needs eyes on IMHO.

 

[Gray0689]

This one really needs eyes on IMHO.

I agree something just ain't right even apart from the under sizing IMO

 

[diamondgas]

:iagree: without 1st hand knowledge there's strange goings on being described...! It'd be handy to have to op's plumber on here to give us the heads up on what they've done so far! Doubt they'd like some of the chatter in the thread mind!

 

[albatross]

Carrera, I have a good read of this and it's the kind of problem that needs a site visit. It's a shame you are so far from me, I'm in Yorkshire, as I would have liked to have got my teeth into it and solved it for you. Saying that try this:

Turn hot water on, turn one underfloor manifold on upstairs, close all the lever valves at the top left of the photo, see if the cylinder heats, if so you have a severe balancing problem.

This may make no difference but it's worth trying. Modern cylinders have high resistance coils and the circuit to the manifolds will have a low resistance as the underfloor pumps take over the work after that.

 

[huddster]

Would it not be worth putting some gate valves on before the lever valves to restrict the ufh circ and towel rads to test weather it is drawing the heat away from the hot water, just a cheap option that might get you by until you figure out a more permanent solution

 

[Ermintrude]

Could just close ball valves ?