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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Thermostat broken (Hortsman DRT2) so heating off. https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1365263366 Message started by godf on Apr 6^th, 2013, 4:49pm

Title: Thermostat broken (Hortsman DRT2) so heating off.
Post by godf on Apr 6^th, 2013, 4:49pm

Hi there.

We had to change the batteries in our Horstmann DRT2 thermostat recently. Then this morning it was indicating that these new batteries were nearly out of power. Two new sets also failed to power it up, so it seems broken.

This means that was cannot turn our heating on at all.

Any advice? Either for turning the heating on by bypassing the thermostat, or for fixing the thermostat.

Luckily it's April, unfortunately it's a chilly April.

We were going to be speaking to the person who fitted it next week anyway, so we'll see what he says, but would quite like to be a bit warmer in the meantime.

Thanks all.

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by godf on Apr 6^th, 2013, 5:04pm

I should probably also mention that our boiler is a sime super 90 plus.

I have no idea how it;s wired up to the thermostat though. Ta.

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by thescruff on Apr 7^th, 2013, 12:15am

Normally you need good quality batteries, is there a chance you have duff ones.

If you need to get the heating on you can add a link between COM-NO with will over ride the stat.

Have you got the manual for the stat.

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by godf on Apr 7^th, 2013, 3:17am

Ta scruff.

I've just tried a new set of batteries, and it came on a bit, but only enough to register that it was low on power, and would not work. I don't understand what would make it suddenly register new batteries as being old, and a quick google has not found other people having this problem.

I've got the instructions, and opened it up. It looks like connecting the com-no wires should be easy. Do I just need to turn off the boiler to do that? Or should I turn off all power?

It's only a couple of years old! We'll try to get a more reliable one next time, ideally one that can be wired to the mains, to avoid this battery trouble.

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by thescruff on Apr 7^th, 2013, 6:40am

Most have a battery back up.

Have a look at the Honeywell DT 90 or the wireless DT 92 much better quality although the price reflects that as well. The intructions etc is on their website.

If you link the old one out for now turn the electric off first

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by CWatters on Apr 7^th, 2013, 9:15am

Screwfix is open on a Sunday..

http://www.screwfix.com/p/honeywell-dt90e-digital-room-thermostat-eco/41365

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by godf on Apr 7^th, 2013, 2:29pm

Ta for the tips.

I think that we want a programmable one, and would probably get an electrician in if we were going to wire it to the mains (the thermostat is right next to the fuse box, but I leave that stuff well alone!).

Anyone could a suggestion for a replacement? If not, I'm sure I can look one up (although last time didn't go so well!).

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by thescruff on Apr 7^th, 2013, 3:56pm

If you want a programmable stat get the Honeywell CM 921 or 927 rf stat.

I have one at home and very very good.

I could tell you how to wire it given the information from you, otherwise a sparky is the best bet.

Title: Re: Thermostat broken (Hortsman DRT2) so heating off.
Post by godf on Apr 7^th, 2013, 4:41pm

Thanks for the offer, but I think I'll pay for someone else to do that one. We're into Spring, so I should be able to have it done at the same time as something else before we really need a thermostat for the winter.

Having to re-programme the old one every year when the batteries needed to be changed was pretty irritating anyway, so it dying could be a blessing in disguise.