Any Intergas experts left on here?

[oldbutnotdead]

Finally getting round to hooking the woodburner up to the thermal store and while i'm at it putting connections in for the eventual gas boiler which will heat the place when i'm too lazy to cart timber in (goes through a fair bit when running the heating as well....)

Plan is an Intergas-looking at the Rapid 32 cos that can definitely run as open vent plus combi, am open to other suggestions but the heat side will be open vent (direct heating the thermal store) and i do want the combi as well (dhw for the 2 bathrooms will come from the thermal store via plate hex, dhw for kitchen & utility from the combi).

Question is really with the pipe layout, all the open vent boilers i've encountered require an expansion pipe running straight ish up from boiler to above the header tank. Is this still required on the Intergas in open vent mode or does the built-in pressure relief valve obviate that requirement? (The install drawings all show pipes running down but I'm no heating engineer so not taking that as gospel)

And follow-up question (in case the more modern Intergas jobbies will better suit my purposes) do they all have the PRV blowing into the condensate drain and the mode switch that allows open vent operation? Suits me fine if they do, i've got power, drainage, cold supply and a roof at the proposed location but no outside wall for the PRV to discharge through.

Before anyone starts i'll not be installing the boiler myself, just want to make sure my plan is feasable so if anyone who quotes tells me i can't do it like that i'll know to bin them off

Ta in advance

 

[dilalio]

Where do you propose to have the feed and vent and don't forget... The pump position would be at the boiler (inside) if I've understood you correctly.

Got a couple of sketches of layout?

You don't want the system see-sawing, nor relying on the PRV for regular relief... It's only really for fault conditions.

 

[muggles]

As with Dilalio, happy to help but more info needed

 

[oldbutnotdead]

Ta both, been working so far from a manufacturers schematic (thermal store lot) but it doesn't represent physical layout properly. Laptop has just pooed itself so will lash an actual pen and paper drawing up shortly...watch this space

 

[oldbutnotdead]

Ok, here is rubbish sketch with many details omitted (things like cold water feeds for dhw, drain cocks, stuff like that).


Distance between store and planned gas boiler is about 2000, woodburner to store is 2500.
The feed & expansion are already on the woodburner (its been running the rads and hot water cylinder direct for the last 18 months). I can get expansion to the top of the store fairly easily (there'll be a 45 degree leg through the wall into the main house) but from the top of the gas boiler would be iffy (its at the far end of a single storey leanto so very long leg at about 10 degrees).

 

[picasso]

Why not put the intergas combi on a phe ? you can seal the intergas and its only one extra pump.

 

[oldbutnotdead]

Why not put the intergas combi on a phe ? you can seal the intergas and its only one extra pump.

View attachment 199673

Thats not a bad fallback plan, ta. Would make a total of 4 pumps on the system, just as well its in the leanto .
There's another potential issue with the ig, it requires a bypass valve (fine) min 6m from the boiler (less fine). Might leave that question for the installer....