Boiler Advice Please

[southcoastboile]

Doing a quote to replace a floor standing hideaway hot water boiler which literally just does the cylinder coil and 2 heating boilers (both Glowworm hideaways).

I normally do domestic and have stuck to Valliant's recently.

I need a boiler to do the heating that is around 70kw. Valliant make one but it is a sealed system boiler and due to the age of the existing pipe work I want to stay away from that and go for an open vented boiler. Has anyone got a boiler in mind that they would recommend?

Thanks in advance

 

[SafeGasInstall]

fit one 30kw and one 40kw heat ony wb cdi

 

[SafeGasInstall]

or fit that 70kw boiler with secondary heat exchanger and a heating pump for the secondary

 

[Ermintrude]

Two logic heat only 30kw or two 35kw vogue heat only?

 

[southcoastboile]

I wanted to fit a wall hung 70kw if poss due to the room. It would be a doddle to get one horizontal flue out. 2 boilers would be a pain fluing wise.
The 70kw I was looking at is a sealed system boiler so was wondering if there are any open vent boilers. Not sure if I would have the head to fit a sealed system boiler without it locking out and don't want to increase the system pressure.
Also when I was on the phone to Valliant tech he mentioned a low loss header. What exactly does this do? regulate the flow to the boiler?
Cheers Safe gas, please could you explain what the secondary heat exchanger would do?
Not ever really done commercial. All I will be doing is fitting the boilers and getting a commercial engineer to connect up.

 

[Ermintrude]

Low loss is basically boiler to a block pumped then block pumped to system. Like a heat exchanger between boiler and system except same water used in both systems and no separation. Boiler pumps to headder and back, system pumps to headder and back. It avoids thermal shock and evens out
Load.

 

[southcoastboile]

Thanks Ermin so is it kind of like a restrictor? and can you recommend a decent 70kw boiler at all?

 

[Ermintrude]

Would say cascade two logic heat only boilers but your right on space ? A concord perhaps? No no a restrictor more like a buffer.