Underfloor heating problems

[justalex81]

that is a positive sign. Any idea on how long each loop is? if your flow meters weren't set up correctly you might be wasting a bit of energy but not massive amounts.

how much does 700-800L of oil cost?

 

[paulmul]

Again, no, I'm not sure as I effectively inherited it some years after the loops were installed. Some must be reasonably long as the whole house is 3360sq ft but downstairs is bigger than upstairs (sunroom and utility have nothing above them), so must take a reasonable amount of loop just to reach some parts. Flow looks to be set a bit higher on the ones further away - is that would you'd expect?

Oil was 57p/litre the last lot I got in December (£513 for 900 litres). I can't get mains gas where I am as I'm in a fairly rural location off the mains gas network.

 

[Ermintrude]

Once the floor is warm and house in use your consumption can be measured.

Reads like flow and return wrong way round on manifold.

That's why heat miser pipe stat thinks it's all satisfied .

 

[SimonG]

I think (hope!) it's the photo. It's basically out the top of the boiler then straight out through the wall at 90 degrees.

Do you get water underneath the flue outside?

 

[paulmul]

Once the floor is warm and house in use your consumption can be measured.

Reads like flow and return wrong way round on manifold.

That's why heat miser pipe stat thinks it's all satisfied .

The flow is USUALLY reading a higher temp than return. Sometimes return shows higher temp by 5 degrees or so. No idea why! Right now it's 43 on flow and 40 on return.

 

[paulmul]

Do you get water underneath the flue outside?

I've never noticed any, no. There's a separate pipe that takes the condensate to a drain. I've never seen any water anywhere other than there.

 

[paulmul]

Just a quick update to thank everyone who replied and to let you know I've managed to resolve both problems.

Firstly, I discovered my stats are just labelled "Pulsar Infloor" which I assume was the company that supplied them. After some online investigation, I now know that they're actually made by Mohlenhoff and are the Alpha Standard model. I'm no expert but they seem to be a fairly cheap/basic stat (e.g. £21.99 on Amazon).

I did some diagnosis with a multimeter and determined that during the 20 minute pause, the stats were still receiving power but cutting off their output regardless of how high they were. All seemed to be on the same cycle, which I assume was because they were all powered up at the same moment by the main switch for the overall heating system. I temporarily hardwired the wires for one of the stats so that the stat was bypassed. The wiring centre showed that zone remained active while all the others did their pause for a minute or so. Next I bought a couple of Heatmiser DT stats (which I'd looked at anyway before any of these issues as they're much easier to control in that you can see the current room temperature). I fitted one in my kitchen and confirmed that, like bypassing the stat, if it was set high enough to be calling for heat, that zone no longer paused.

Next I went to replace my sunroom stat (the one that seemed to call for heat continuously unless I set it lower than the adjacent kitchen one). On removing the old stat, I immediately noticed that there was a bad draught coming down the conduit carrying the cables to the stat. Little did I realise the stat was being cooled from behind! I sealed around the cables at the end of the conduit, stopped the draught, fitted the stat, and left it all running for 24 hours.

I now have a kitchen and sunroom at a comfortable 20 degrees, and those zones heat when they need heat and stop when they don't. No more 20 minute cycling.

I've ordered 4 more Heatmiser DT's to replace the remaining Alpha stats. I've no reason to suspect I won't then have a system that works exactly like I'd expect it to!

Again thanks for your suggestions and advice.

Paul.

 

[jonnyswamp]

Sounds promising