2 or 4 pipes from an insert stove with boiler

[drorrie]

Hi

We had a charnwood insert stove with boiler (slx45i) installed a fortnight ago and the plumber (our regular guy) only used one flow and one return. Then the charnwood rep (also a plumber) had to come out cos a handle was broken and he took one look and said its installed wrong and needs 2 flow & returns. So long story short is we got a different plumber to come look at it cos we were annoyed by regular plumber and this one said ' its all well and good using 4 pipes in a new house but 2 should do you' because we already had a back boiler before the stove so its pipes were used. He thinks its not worth the hassle or money to put the two extra ones in. he also said we shouldn't have plastic pipes but I know they're everywhere in our house (following an extension). I've had a good read on the forum re plastic vs copper but is there anything about not using it with a stove? The pipes at the stove boiler and into our hw tank are copper.

I'd really value some other thoughts on this issue. I have read that using the same flow & return for hw and rads can short circuit the boiler-what does this mean. Other than inefficient heat output will it cause damage?

I should say-its being reinstalled no matter what, as the first guy hasn't a straight eye at all and its not level on 3 planes, so now is the time to put in the extra pipes if needed.
Thanks

 

[Dan Robinson]

2 or 4 pipes is totally dependant on the type of installation.

Plastic pipework should not be used within close proximity of a stove, but I am not qualified to say anything more than "within a couple of metres guv".

You would hope the manufacturer's "rep" would know more, but that is not necessarily so.

As far as my stove knowledge goes, you need a gravity circuit venting direct to he F&E, then anything else can tee off as long as it doesn't short-circuit.

 

[dcawkwell]

Read the instructions for the stove. They should go into
great detail about what is isn't right for the particular stove.

From my personal knowledge you are dealing with an uncontrolled
heat source so plastic pipes are a no no.
Also 4 pipes are require as you need a gravity heat leak or you will
get kettling in the boiler should there be no circulation.

Personally I wouldn't have anything to do with wood stoves. The novelty
soon disappears and they stay unused.

 

[Norcon]

Two pipes are fine in conjuction with an injector T. The gravity circuit must be installed as per MI's.
If its practical you could fit a third pipe as per charnwoods MI's. But T'ing on the gravity flow at a more practical level to the CH is fine.

Hi-Lo stats are important with either 2,3 or 4 pipe configurations.
The gravity circuit is partuculary important as it will be the catalyst to trigger the LO stat which will energise the pump.
The Hi stat has a secondary purpose energising the pump should the gravity circuit fail.

The positioning of the LO stat on the two/three pipe setup should be downstream of the injector T where it senses both gravity flow return and CH return flow so will provide good protection for the boiler.

 

[drorrie]

Personally I wouldn't have anything to do with wood stoves. The novelty
soon disappears and they stay unused.[/quote]

No novelty in this house! We've had a fire with back boiler for 10 years which we used 5-6 days a week autumn thru spring! Plus we have or own supply of well seasoned hardwood to burn so multifuel stove makes sense for us. But I'm sure plenty of people put them in and don't use them.

 

[Norcon]

Also read page 17 here....
http://www.woodwarmstoves.co.uk/_assets/manuals/new instructions fireview march 2010.pdf

Charnwoods manual has scant information on the HI-Lo stat set up.
Woodwarm explains it well and the physics will be no different to your boiler. And also shows the wiring diagram.
Read and study it carefully. Unfortuanetly you might have to educate your installer.