How to control second pump from Worcester Greenstart boiler?

[nhand42]

I've got a Worcester Greenstar 18i System boiler with integrated pump. The optional DT10RF controller has been installed. The boiler is used only for central heating.

I've also got a Wilo pump with three-way blender mixer connected to the underfloor hydronic pipes. The three-way keeps the hydronic loop at 45C whereas the boiler loop is more like 70C.

Currently the Wilo runs 24x7 from a socket on the wall. The boiler turns on and off as decided by the DT10RF thermostat. I'd like the Wilo pump to also turn off when the boiler turns off, but can't figure out how to do it.

The LP/NP terminals on the Greenstar seem to be disconnected; my multimeter shows 0V at all times. There are no LZ/NZ terminals like on the Greenstar 18i Regular model. I don't see any other switched lines from this boiler.

Is there a switched line somewhere I can use to control the Wilo pump?

 

[Ermintrude]

No you need a thermostat and programmer to run your underfloor with a pipe stat and two port which turns on and off the the boiler not vise versa

 

[Worcester]

Your u/floor heating pump should be being controlled by the ufh contol system, it shouldn't be plugged into a socket and shouldn't be on 24/7

Whoever installed the ufh heating system controls should come and configure it properly, get them back

The DT10RF is not an ufh controller.

 

[IDCHAPPY]

Your Wilo wont last long being on 24/7...

 

[Nostrum]

If the boiler turned the UFH off, what's going to turn the boiler back on?

 

[Ermintrude]

If the boiler turned the UFH off, what's going to turn the boiler back on?

The doorbell by sounds of it

 

[Nostrum]

Ding dong, heatings on.

 

[nhand42]

If the boiler turned the UFH off, what's going to turn the boiler back on?

The DT10RF has a wireless room stat. It turns the boiler on when the room temperature drops below the set temp.

The problem is nothing is the pump is always on. The system "works" as far as the room temperature is correct and the boiler only heats when needed, but I'm unhappy with the pump running 24x7.

 

[chris watkins]

Begs the question if heating only why have a blending UF manifold? Just turn the boiler stat to 50, sounds like a diy install to me!!
Who's UFH kit have you got installed nhand42 ?

Welcome to the forum by the way.

 

[nhand42]

Begs the question if heating only why have a blending UF manifold? Just turn the boiler stat to 50, sounds like a diy install to me!!

Builder installed it. Then he went bankrupt and left me in the lurch. Plumber is long gone and based on some other dodgy crap he installed I'm not getting him back.

Who's UFH kit have you got installed nhand42 ?

There's the Wilo pump and a blender (hot in, cold out, mix up, and mix return). The hot and cold go to the boiler. The mix up goes to the hot manifold. The cold manifold goes to the mix return. It's a concrete slab hydronic. The pump is plugged into a 240V wall socket in the airing closet. If it's got a UFH controller then I haven't seen it.

The boiler has the DT10RF with the wireless room stat. The pump runs all the time and the boiler is switched by the room stat.

 

[AWheating]

You need external controls by the sounds of it. Also you need to be gas safe registered to remove your boiler case, get a decent heating engineer in who is gas safe and can wire controls.

 

[Worcester]

Pictures please

What make is the ufh manifold?
How many rooms does it serve?
Are their any actuators on the manifold?
Apart from ufh (and hot water) do you have any radiators?

 

[josh]

Sounds like a complete bodge.
The only way your gonna sort this is by paying someone that knows what their on.
I bet the manifold flow returns are teed of from the nearest rad.

 

[Ermintrude]

Josh knows a lot about this??????

 

[josh]

Josh knows a lot about this??????

how i do them mate, tee of rads, on a plug, there you go luv I'm a heating engineer

 

[Bronze_tap]

I've got a Worcester Greenstar 18i System boiler with integrated pump. The optional DT10RF controller has been installed. The boiler is used only for central heating.

The LP/NP terminals on the Greenstar seem to be disconnected; my multimeter shows 0V at all times. There are no LZ/NZ terminals like on the Greenstar 18i Regular model. I don't see any other switched lines from this boiler.

Is there a switched line somewhere I can use to control the Wilo pump?

So first look for some docs:
Greenstar 18i System literature - Worcester, Bosch Group UK installer site
www.worcester-bosch.co.uk/cache/file/482/gas-boiler-wiring-guide.pdf
look from page 93.

1. It may be necessary to mount additional dual pole relay (contactor) controlled by the room thermostat, which will send a signal to boiler (from one pole) and a pump (other one).

2. Another option can be a cyliner-style stat on a CH flow pipe, set to 35 or so degrees, that would run the pump, only when the pipe is warm/hot.

PS: Had a really fun job yesterday, fixing faulty aircon (water cooled) in my lab, with bodged electronics controls - a roomstat in a fan circuit + half open the control walve and off we go. Before there was 5-10 different guys from HVAC servicing being sent there by building manegent (last 3 month) trying to fix thing, and they other leave it fully on or off. Nobody thought about controlling a fan with separate mechanic thermostat for 15GBP...

 

[Ermintrude]

They have the mental agility of a rabbit dropping

 

[Bronze_tap]

Bodge tip for the builders: Next time just connect an underfloor loop in series with a big rad on the return, and saved a fortune on a mainfold/pump Provided rads are big and their return is always bellow 45 degrees, and the loop is in 22mm or bigger pipe, you should be ok...

 

[nhand42]

Thanks for the helpful advice.

Looked into the wiring. The original installer - I'm assuming the plumber - had wired the pump on the boiler. No wonder it didn't work properly.

Wired a Danfoss thermostat to the boiler and another relay off LR to switch the pump. Now the pump and boiler turn off and on together. Too easy.

 

[Dotty]

So now you've freely admitted that you've broken the law by opening up your boiler.

In order to save a few pence you've put your family's lives at a very real risk of death.

You're a mug. Turn the boiler off and get a gsr in.

You do not possess the competence to ensure the combustion seal hasn't been compromised.

I've edited your thread to prevent other people in the future from acting so stupidly.

Thread closed.