Firing up newly laid UFH

**davemul** · 18-10-2011

Guys how long do you leave the UFH on in the periods of 'running in'

and what temp do you start at?

Looking to switch on the bathroom UFH (and kitchen) soon.....

Would the below be ok

On 1st day evening starting at say...15 degs.. leave for a few hours then switch off

2nd day same time, 20 degs leave for a few hours switch off...

then repeat untill max temp is reached?

or are 5 deg increments too much?

thanks
Dave

**Sir Ramic** · 18-10-2011

I would start at the minimum temp then increase daily by 3 to 5 degrees until full temp reached.

**Phil Hobson** · 18-10-2011

As Neale for me, I always recommend no more than 5deg in any 24hrs on the way up until optimum temp reached, hold at that for 48hrs then decrease no more than 5deg in any 24hrs. This allows for expansion and contraction. I would also leave 2 weeks after tiling before firing up the ufh, just to let everything cure, maybe a bit OTT, but thermal shock can be a nasty thing.

**davemul** · 18-10-2011

keep the ufh on for 48 hours!?

**Alan.P** · 19-10-2011

Yes leave it on, and also, don't turn it off in-between turning it up, turn it up 5 degrees at a time ( per day ) and leave it on, your trying to give the screed every opportunity to expand to it's limits, and to shrink again. Why do you seem shocked at the leave it on part out of curiosity ?

**davemul** · 19-10-2011

seems a long time to have it on.. once run in our UFH is only going to be switched on for say 3-4 hours morn and same in the eve
by my calcs.. id I start off at 10 degs...and max is 30 degs. IF I go with 5 deg intervals.. that will be 10 days solid that the UFH will be on....

sounds excessive to me, not to mention expensive! I have another 2 zones to do also

EDF will be coming round worried!

**Alan.P** · 19-10-2011

Don't forget, it's on yes, but through a stat so once it's up to temp it will knock off and kick back in again, it's not going to cost a fortune to commission it right now but could cost a bit to put it right afterwards.

**Stewart** · 19-10-2011

They don't cost much to run and can work out cheaper to leave on rather than tuning it off and on and having to heat up from cold again. Mine stay on all winter.....

Created on iPhone.....

**Fliselege** · 10-01-2012

Our electricians say not to touch the ufh for as many weeks that you have cm's of screed, when we do bathrooms we're supposed to have min 4cm of screed some times goes much higher around edges to get fall to floor drain so in some cases for exapmle there's 8cm screed so no ufh for 8 weeks, then they can whack it on warp factor 6.