UFH Commissioning

[ianR1]

So finally the screed was laid and I have awaited my allotted time and have now started to introduce heat into the system.

 

I was recommended to increase the flow temperature by 5 degrees every few days until a maximum of 55.

 

We are now up to 35 degrees flow temperature and the house is up to 22 degrees.

 

Is there a requirement for me to keep turning this up until I reach 55 degrees ?

 

What normally is the ideal flow temperature and what sort of loss should I see on the return temperature ?

 

I have roughly 450M of pipe over 5 circuits ran off a wavin manifold and a heat only boiler.

 

Thanks in advance.

[jayc89]

42 minutes ago, ianR1 said:

Is there a requirement for me to keep turning this up until I reach 55 degrees ?

 

Yep, if nothing else, it helps dry the screed out. Once up to temp, make sure to also turn it off gradually too (normally by 10 degrees a day)

 

42 minutes ago, ianR1 said:

What normally is the ideal flow temperature and what sort of loss should I see on the return temperature ?

 

Flow temp should be house specific - floor/wall insulation, window sizes, final floor finish etc. - did the company you bought the UFH kit from provide any heat loss calcs? Based on each room's heat loss, you can work out the required W/m2 and go from there. Here's a rough guide I used for mine (150mm pipe centres);

 

 

Return temps generally depend on your flow temp. If the flow is less than 30 degrees, go for a return temp ~ 4 degrees lower. If it's more than 30 degrees, go for ~ 7 degrees lower. The delta-T can be managed by adjusting the flow rate on each loop until each one is something like.

Edited October 10, 2021 by jayc89

[ianR1]

Thanks for your reply.

 

I was running it without the actuators on and the thermostat cranked up to allow for everything to heat up equally but i'm thinking I may have to fit them now or its going to get too hot in here or would you recommend just riding it out until we hit the 50 mark and back down again ?

 

I sourced all the kit myself and installed it and just had a plumber friend make the boiler connections so I don't have a heat loss calc, looks like something i'll have to achieve with trial, error and patience !

 

[jayc89]

I'd probably stick the actuators on, unless you're enjoying the sauna experience

As a rule of thumb, when I was doing mine, I got the delta-T on each loop to ~ 7 degrees by adjusting the flow rate and then slowly increased the flow temp until each room was comfortably reaching the thermostat temp, any hotter and you risk your room temps overshooting.

 

I used the heat loss calcs to guide me in the right direction, but my setup's currently running a flow temp 10 degrees cooler than the calcs suggested I would need...

 

Good luck!

[Fly100]

The Salus Auto actuators are very good, do all the balancing for you.

[ianR1]

I shall look into them, just need to make sure they will fit on my manifold as mine are clip on and they appear to be screw on and they will be work with the honeywell evohome system

[ianR1]

On 10/10/2021 at 21:47, Fly100 said:

The Salus Auto actuators are very good, do all the balancing for you.

 

Thanks for the recommendation, I have fitted these today and am very impressed.

 

 

[Fly100]

9 hours ago, ianR1 said:

 

Thanks for the recommendation, I have fitted these today and am very impressed.

 

 

Made a big difference to my setup.

[Jimbouk]

Interested as to why they cannot be used with Heatmiser thermostats?

[Fly100]

2 hours ago, Jimbouk said:

Interested as to why they cannot be used with Heatmiser thermostats?

 Thats old bit of info,  which they fixed a while ago. I have Heatmiser and they work great.