CH Upgrade to 3 port (few questions)

[sotal]

I've just spent the weekend installing a Danfoss Heatshare pack, new pump and TRV's to all the rads (except 1).

All plumbed in and all works with no leaks - just a few questions now!


Q1. What Speed Setting should I put the Grundfos 15/50 pump on? I've currently got it set on 3 (the fastest) - is that correct? - I have 8 rads in the house, what would having it on too high or too low do?

Q2. Since installing the kit the rads are much hotter than before - too hot to keep your hand on (before I couldn't get them that hot). What has made them that much better? Is that just the pump?

Q3. As above, what's the best way to reduce the temp? I can either turn the TRV's down or turn the dial down on the boiler - which is more efficient? My idea was to turn the boiler down first then adjust each room accordingly - is that correct or should I leave the boiler alone and just adjust the TRV's?

Q4. With the kit I got a cheapy room stat, I've also got a Digital Room Stat which I was going to use but the wiring seems different. The manual one has 3 wires going to it - (N COM CALL). The digital one only has two wires (NO NC) - the digital one has batteries which go in it so my guess was I don't need the N one? If that is correct which do I connect the others to?

Q5. The instructions talked quite a lot about boilers with overrun being better. As far as I am aware my boiler doesn't have overrun (it's never overrun before - the pump and boiler both instantly switch off) so I've wired it up as per the diagram without overrun. Is it any major disadvantage to not have overrun?


Here's some details to help:

8 Rads in house
House is 4 bed detached
Boiler is a gloworm probably 30 years old (can't remember model but it's something like 380)

Problems before were:

Pump was noisy.
Central Heating and Hot water always came on together before
Heating just kept heating there was nothing to stop it at a given temp
Hot Water was getting scalding hot during winter
We had to have the heating come on during summer to heat water or go round and switch off all the rads

 

[ChrisR]

Q1 try speed 1, which will tell you iof the rads are balanced (see faq on that) because it isn't likely to be fast enough for 8 rads. They should all gwt warm though. (Open all trv's WIDE)

To set things up you really need a surface thermometer- about £15.

FOr a normal (old non cendensing) boiler you want about 11 degrees across the boiler, and rads. Temp drop is liable to be too much on speed 1, try speed 2 (.....or 3)


Q2,3 boiler stat knob sets rad incoming temp. Adjust according to time of year. Currently around half way.


Q4 yes digi stat will just be a switch. Connect to common and call of old stat.

Q5 There are Zillions of old GW's but they mostly wouldn't have had overrun.
You can add a pipe stat and wire it up if you're handy with that sort of thing - are you?!!

 

[sotal]

Thanks for the prompt reply.

On Answer 4, do they connect a certain way round?

On Answer 5, I'm perfectly capable given enough instruction, but it's probably a bit beyond me without instruction! - I had no problem wiring up all the stuff for the central heating pack, and I had no problem fitting all the TRV's and new valves on all the rads and no problem doing the pipe work. (but all of that was following the installation instructions!)

 

[ChrisR]

Q4 - not really.

Google pipe thermostat, then it's just a matter of locating your wires. Stat clamps on the flow pipe from the boiler, set to suit - try 45 for a start.. Pretty simple.

 

[sotal]

That looks easy enough to do.

My biggest problem would be that it requires another cable to be run from the airing cupboard (where the pump is) to the boiler which is in the back of the garage.

I've had a quick google for pipe stats and all the products which come up just seem to be cylinder stats are they basically the same thing?

 

[sotal]

http://www.avenuesupplies.co.uk/ind...ers+&+Thermostats+Cylinder+&+Pipe+Thermostats

That's the sort of thing I got from my searches.

Would that be correct? I'd just need to run the 3 core through then.

 

[sotal]

Can I just put the stat on the flow pipe when it actually gets to the airing cupboard?

That way I wouldn't need to run any extra cable. How long would you expect the pump to run for - should it be 10 mins or so extra?

Cheers

 

[sotal]

Well I bought a pipe stat - connected it to the flow pipe coming into the airing cupboard and attempted to wire it up but once wired up the system doesn't run correctly


I've returned the wiring back and all is fine, can anyone just confirm how I should wire it up?


The thermostat has the following connectors:

1 - Live
2 - Break on Rise
3 - Make on Rise
E - Earth


So obviously I connected the Earth up, I then connected the Pump to 1, "permanent live" to 3 and "Boiler on" to 2.

It didn't appear to work correctly.

As a second attempt I figured I'd just got the switch the wrong way round so I connected 3 and 2 the other way round.

It now fired up but only if I move the temp below the current measured temp on the stat. So that's backwards so surely the first way was correct?

Now I'm confused - I thought I had it all sorted in my head!

 

[sotal]

Woops, think I'm sorted now, was right the first time just the temp was high enough so the room stat wasn't calling for heat!