Penzance Passivhaus

[Mkgolder]

Hi guys, 

Just joined this group. 

Just finished building a Passivhaus in Penzance, Cornwall. 

My friend and I built 2 houses together, one for each family on a challenging plot chasing the passivhaus dream... 

 

We've been in the house since end July and just seeing how it copes with our first winter! 

 

So it's a timber. Frame design, sitting on a concrete raft (on 30cm insulation!) planned using the PHPP software to conform to PH standards. So it's super insulated, airtight (0.3ac/hr) no cold bridges, triple and quadruple (skylights) glazed with Brink MVHR system (ubbink plastic duct and plenum). 

 

My friend developed the wall buildup himself to achieve the PH standards without us having to buy premade PH timber frame sections, saved us a lot of money... 

 

Biggest struggle so far, trying to get the. Brink post heater to operate... It's wired up correctly but won't operate, even at high fan speeds...? Which is really why I joined this forum, to hopefully glean some info as our supplier hasn't solved it (or Brink at this stage!) 

 

Cheers.. 

Murray 

[Jeremy Harris]

Welcome.

 

There are a few of us here in the "passive house club", and I think many of us have struggled a bit with trying to get commercial kit to function as we wish for the particular demands of a very low energy house.

 

Our build uses a similar 300mm thick insulation passive foundation system by the sound of things, but despite having the option to use the air-to-air heat pump that's built into our Genvex MVHR, we opted to fit UFH, which we've found gives a more comfortable form of heat, although our slab never really goes above about 22 to 23 deg C, and mostly sits less than a degree warmer than the room temperature.

 

I'm not familiar with the Brink post heater system, I'm afraid, but if it's electrically driven it should be relatively straightforward to trouble shoot, I'd have thought.  From your description it seems like a control system problem, do you have a wiring diagram for it we can look at?

[Gone West]

Hi Murray, welcome to the forum. We have also built to PH standards using a novel wall construction. We use three electric towel rails to heat the house which is supplemented with warm air heating from a Genvex Combi 185. Is it possible to bench test the post heater?

[Mkgolder]

Hi guys, thanks for your quick responses... I've attached a copy of the post heater schematic... Nothing too exciting.... 

We haven't been able to bench test the heater because it requires airflow to function.. 

 

Brink suggested we run it at high speed to test, but it should work at low speed anyway?! It appears that the temp sensor in the heater limits its use and the airflow sensor oscillates between on and off... Our electrician tested it and watched the thing cycle... 

Not sure what to do next? 

[Jeremy Harris]

I'm pretty sure it won't work at low speed, as the air flow rate will be far too low and the heating element would just try and cycle on and off quickly.  Our post-heater (albeit driven by a heat pump) will only come on when the MVHR is running at boost speed, just to get enough airflow so as to be able to distribute even a small amount of heat.

 

Based on that I'd say Brink are right, but I would have expected their control system to automatically boost the fan speed when the heater comes on, as that's what happens with our Genvex unit.