Archive for the ‘HVAC’ Category

I can’t believe they did that TOO!

The A/C compressor is oriented the wrong way. So the back of it faces the hot south Texas sun and draws warm air in to cool the fins and blasts the hot air out towards the house. And the ‘nice’ side with the somewhat acceptably looking access panels faces the house and the ugly back of it faces out! But it maybe saved a few inches of refrigerant pipe so that’s all right then!

I can't believe they did that TOO!


Categories: HVAC, Uncategorized

Kitchen and A/C going in

We are 2 days through a 3 day installation of the kitchen cabinets. Then comes the counter tops.


photo photo2







The A/C wall units are in. There are three of these, and three concealed mini-ducted units.



The concrete pad for the A/C compressor has been poured.



The A/C compressor was here but was taken away again, it needs to wait for the concrete pad to cure.



Categories: HVAC, Kitchen

Inspections Passed

On Monday we have a 5-way inspection: Electrical, plumbing and mechanical (HVAC) rough-in, framing and stucco. There were 7 failures. These were fixed and on Tuesday it was re-inspected and there was 1 failure. The failure was with the HVAC and was down to the fact that the inspectors have never seen an HVAC system as sophisticated as ours before. They said we need to add float switches and drip trays to each of the zones. Float switches detect back-up in the condensate line and cut out the power the compressor, but these system include integral float switches and are networked to the compressor. Our project manager went to the manager of the inspectors today and had a word with them, and now today we have passed all inspections and are approved to the next stage which is insulation.

The guys are finishing off the standing seam metal roof, it should be finished tomorrow (Sat) and if not Monday, and the framers are putting on the Hardi panel soffit. The Hardi soffit looks really nice and it hasn’t even been painted yet. It will be finished next week and painted the same cream color as the stucco.

Mr Slim Wall Mount

February 8, 2012 Leave a comment

Mr Slim Wall Mount

Categories: HVAC, Uncategorized Tags:

Honeywell RedLink

January 26, 2012 Leave a comment

I finally finalized the spec of the HVAC system today and placed the order. It only took 11 months and discussions with 5 different suppliers to get a sensible proposal. The final system has six zones, all individually controllable  consisting of three wall-mount units like this:Mr Slim Wall Mount

and three mini ducted units in drop ceilings like this:

connected to a single outdoor compressor like this:

But the really clever bit is that the latest units are Honeywell RedLink enabled. RedLink is a proprietary Honeywell wireless protocol. Every unit communicates wirelessly over RedLink to an internet gateway that plugs into the back of your router like this:

You can control the units from the Honeywell Total Connect Comfort website or from an app on an iPhone or iPad:

and the good thing is that the price is quite reasonable. The gateway is only $100 or so versus the over $1000 commercial solution that was originally proposed. The fact that this system is wireless rather than wired makes installation cost lower too.
All the latest Mitsubshi indoor units are RedLink -enabled which means they talk to the Honeywell gateway. There are also other accessories you can get like an Outdoor air temperature sensor. And I guess the range may be extended later.

RedLink Outdoor air temperature sensor


RedLink is a new system for Mitsubishi which they appear to have licensed from Honeywell. It’s only available in March this year from Mitsubishi so I will be one of the first. Let’s hope it works OK. It seems more consumer-friendly than the previous rather industrial system Mitsubishi had, which was mainly aimed at owners of large commercial buildings.

More info on the Honeywell Total Connect Comfort system

A/C System, Manual J and sizing zoned systems

The only thing that is holding up submitting the plans is the ‘Manual J’ calculation which is the A/C heating and cooling loads. The A/C system I specified is the Mitsubishi City Multi Series S which I zoned into 6 zones (it can take a maximum of 8 indoor units, I plan 6). Instead of a central air handler and air ducts around the house there’s refrigerant pipes from unit to unit, and each unit is separately controllable via a iPhone or iPad app called MeZo from anywhere in the world with a connection.

You can have to up 130% indoor unit loads on the single external 4-ton (48,000 BTU/hr) outdoor unit which is infinitely variable in speed. ie a 4 ton unit can have up to 5.2 tons of internal loads. I have 129% of the outdoor unit loads in indoor units planned. Which means I can’t cool everywhere to 75 degrees F in the middle of the day in the middle of summer all at the same time. Instead I can direct it where I am.

Just got a call from the A/C guy. He is panicking. “The total A/C load is at least 4.8 tons, maybe over 5 tons! This isn’t big enough!”. Well….yes…….That is the whole point. It is zoneable. Maybe you can’t have the living area, the bedrooms and the workshop all cooled to 75 F  at noon in the middle of summer. But why would you want the bedrooms cooled in the middle of the day? The whole point is that you only cool the bits you use. That is the point of zoning!

And this guy is supposed to be an expert on eco-friendly HVAC solutions.