heat transfer wiring puzzle

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norman1nz

9 posts

Wannabe Geek

#150838 4-Aug-2014 23:43

Hey guys,
Wasn't sure where to post this but hopefully someone clever with some knowledge of timers or thermostats could help figure this out..

I have a two storey house with wood burner in the upstairs living room. I've put in a smartvent FAN0338 heat transfer kit that kicks in when the living room gets over a threshold such as 20deg. This can bring up the temp downstairs several degrees, but it's still very damp.

I've bought the DCT1481 'summer kit' for the heattrans which includes a filter the same as their positive pressure system, and a damper that can be powered open between the woodburner heat source or external (in my case the roof space so as to make it into a HRV/DVS type system).

In winter I want to source the air from the warmest of either the roof, or living room with woodburner, and turn the system on when either is over the temp threshold.
In summer I could use effectively in reverse with the door in the stairwell shut. It would extract hot air from living room and with the southern living windows open act as a summer feature.

Now I could achieve most of this with a manual switch on an 8 hour timer which changes the damper to source from living room, if I dropped the heatrans thermostat threshold very low.

Otherwise I'd prefer if I could install a thermostat in the roof to engage the damper automatically at the right times and turn fan on.

Would this be feasible / possible?

This diagram helped clear up in my head what I'm trying to achieve - hope it makes sense

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8042 posts

Uber Geek

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#1102285 5-Aug-2014 01:23

Taking a step back, what is the core problem you are looking to solve?
You mentioned dampness and this raises immediate flags withs me to address the water/moisture issues at the source first, before looking to ventilate...

charsleysa

597 posts

Ultimate Geek

#1102289 5-Aug-2014 03:31

I would suggest you get some hardware that can connect to a raspberry pi and see if there is any existing software for this kind of stuff.
Hardwiring this looks like it's going to be a massive bundle of cables, then again I'm not a ventilation systems expert.

Regards
Stefan Andres Charsley

BTR

1527 posts

Uber Geek

#1102602 5-Aug-2014 13:22

What is the actual issue you are trying to correct, is it a heat issue or a dampness issue as a heat transfer kit won't fix moisture it will just move it around.

norman1nz

9 posts

Wannabe Geek

#1102644 5-Aug-2014 14:22

Hi guys.
Ok some more background:
Last year I added an extra 50m2 underneath my house, but being on a south facing hill slope, there is next to no direct sunlight hitting it.
Foundations are concrete with poly underneath, batts in the walls and the ceiling of both floors, new single glazed (regretting this decision) joinery with thermal curtains, but there are two problems:

1) Heat in winter is typically 10-14deg downstairs, around 3-5deg cooler than upstairs before firing up the woodburner.

2) Dampness - I've got a MJ-E26VX dehumidifier downstairs which drops humidity from 80% to 60% in a day and collects about 5l of water, but after another day of being turned off the humidity will be back up to 75-80% again.

I'm wanting to use the existing heattrans system when woodburner is cranking upstairs to transfer excess heat downstairs - this already works better than I expected. Having it running all day with stairwell door shut and the fire cranking can also drop humidity to 50% too :-)

I also want to transfer air from the roof cavity when the woodburner hasn't been running (and the living room is cool) using a HRV/DVS style system.
As I want to use the existing air ducting / vents from heattrans (I can't put more in now the building is finished), I have purchased the summer feature for this - for which I'm planning to put the filter (same as all DVS/HRV/PP system filters) high in roof cavity instead of outside.
This gives me everything I need except a control unit and a few extra thermostats. (the summer feature is designed to have damper changed via a switch you flick on in summer and off in winter).

So.... All I need is some alternative to the brain/thermostats so I don't have to flick the switch on and off when temp changes like morning or afternoon / evening / night

Raspberry Pi would be perfect and fun to get up and running :-) Maybe a bit overly complex and not sure about sourcing / connecting the components... Suggestions?

tchart

2380 posts

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#1102657 5-Aug-2014 14:59

What's the budget? You could use WeMo plugs with a NetAtmo weather station. Control could be via IFTTT which supports time based rules as well as triggers such as NetAtmo temperature etc. NetAtmo's have come up on offtheback.co.nz for $120 a few times recently.

norman1nz

9 posts

Wannabe Geek

#1102678 5-Aug-2014 15:27

tchart: What's the budget? You could use WeMo plugs with a NetAtmo weather station. Control could be via IFTTT which supports time based rules as well as triggers such as NetAtmo temperature etc. NetAtmo's have come up on offtheback.co.nz for $120 a few times recently.

Looking good :-)
The system has cost me about $1300 so far just in components so another 200-300 to get it working really well would be money well spent..!
With smartphone control it's looking similar to the smartvent Evolve system which is almost $3k just for components, then extra for the heattrans functionality of it :-)

Niel

3267 posts

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#1102756 5-Aug-2014 17:59

Run the dehumidifier for a week to dry out the furnishings, not just a day.

You can never have enough Volvos!

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

timmmay

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#1102830 5-Aug-2014 19:56

I'd be wanting to work out where all that moisture was coming from. A DVS system set to run from say 9am to 3pm would be better than a dehumidifier, it'd blow all the moisture out but not cool it down running at night.

Jaxson

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#1102939 5-Aug-2014 21:49

Yeah where is the moisture coming from man?

Sort it, rather than blow it around the rest of your house.

mclean

581 posts

Ultimate Geek

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#1102974 5-Aug-2014 23:01

What voltage is the damper actuator, and is it driven both ways or spring return?

norman1nz

9 posts

Wannabe Geek

#1103036 6-Aug-2014 08:22

I've been running dehumidifier for about 2 months straight now until it fills up and needs emptying.

I have no idea what'd be causing so much moisture unless it could get through unpainted hardiflex on the otherside of the wall, but then that'd make my batts wet right?
Only vent is the shower outlet which has a timer on it for 7mins after turning off and dampness recurs without using shower.

Damper is driven both ways. It and the fan are both 240V

timmmay

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#1103038 6-Aug-2014 08:24

Could it be coming up through the floor? Concrete is permeable. Also have a look at the sources here.

norman1nz

9 posts

Wannabe Geek

#1103045 6-Aug-2014 08:47

The concrete was covered with sand then polythene before concrete poured but plumbing is within this concrete above polythene..
No pools of water anywhere but I store my firewood under the house and it's always damp - might pop my humidity reader under there and compare with someone elses house.
Nothing else from the sources link would apply except single glazing.

Very interesting to read that (EECA) recommends that the supply air of home ventilation systems be sourced from the outside, not from the roof space. But I've already bought and opened the kit..
It has a filter which is fairly cheap to replace each year ($80 plus cost of fan I guess is getting close to cost of running dehumidifer anwyay)

timmmay

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#1103046 6-Aug-2014 08:52

I bought some extra air piping and an eve vent kit, when I get around it I'll extend the hose on my old DVS to reach outside. Not sure it'll have the power to push much air through, but I can smell the roof cavity contents.

mclean

581 posts

Ultimate Geek

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#1103110 6-Aug-2014 10:00

Not exactly what you asked for, but can you do something like this?

The thermostats can be separate devices (one in the loft and one in the lounge), or a 2-channel controller with remote sensors which would let you adjust the set-points from one location.

If you can find double-pole thermostats, or a controller with two output relays per channel then you can eliminate the contactors/relays. But those might be hard to find.

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