More Boiler Porn

This is my new boiler installation, which I posted a while ago on my reno blog (south slope reno) but since everyone is loving these photos, why not do it again? Since now we have some experience running it.

This is a Lochinvar Knight KB150 modulating condensing boiler, with an indirect water heater (TurboMax). This is supposed to be one of the most energy-efficient configurations available. The boiler is over 95% efficient and qualifies for Federal and Keyspan energy rebates. It’s hydronic baseboard, but is supposed to be even more efficient at radiant heat.

It’s set up with four zones.

One zone is for the entire first floor; LR, bath, kitchen, DR.

One zone is for the second floor minus the guest bedroom, i.e., MBR, master bath, and office.

A third zone is set up for the guest BR so we can keep that low when it is not in use.

The fourth (unused) zone will be used for the basement when we get it to be somewhat more finished.

Naturally each zone is controlled by a programmable thermostat set to our needs.

We had agreed to do some of the pipe insulation and my wife discovered she likes it, so we got a little carried away with that part of the job.

We’re going to get some of the control wiring a bit more protected next week (the blue cable at right is a network cable that fed my computer when it was in the basement and is not part of the installation).

The intake goes thru the wall (the house is semi-detached) and the exhaust is run thru PVC up to the roof, using the old chimney as a chase to hold it.

There has been a steep learning curve on this boiler for all concerned, and we have had one visit from the factory rep, plus a few from the installer. It took me a couple of weeks to notice that we were getting numerous temperature overshoot and high limit errors.

The factory rep as well as the installer discovered a couple of silly things; the return sensor was cable-tied to the pipe. When my wife insulated over it the sensor was dislodged. So we solved that by putting it in a well. The second thing was that the outdoor temp sensor was giving faulty readings because when the cable was run along the ceiling, one of the installers managed to put a staple thru it!

At the same time, this boiler is designed to run and to do ‘soft lockouts’ so it will provide heat and hot water even if there are considerable errors such as we had here. The downside of this is that if you don’t pay close attention you won’t notice the problems until you get your gas bill! And December to January was almost as high as the old Weil-McClain steam boiler we had before we started renovations.

After we corrected these problems, and made some programming changes, our bill for Jan/Feb (one month) was $280, and that was including one week when the boiler was still not running correctly. So I’m hoping to get a gas bill of around $200 for this month (and that includes that Wolf stove, lol).

One thing I learned is that these boilers are just big computers. There are dozens of variables that can be programmed in, and installers don’t know all of them, and even the factory rep that was here left the boiler not ramping up quickly enough.

While my installer didn’t want to hear this (same as the AC guy), since he claims mis-programming by homeowners causes him huge problems, it behooves the savvy homeowner to carefully RTFM and learn what each programming option means and experiment as necessary (but never change more than one option at a time so you can roll it back if the results are unexpected).

Meanwhile the circulating pump for the guest bedroom failed (sounds like a bearing failure), so we’re just leaving the door open so the GBR picks up enough heat from the rest of the floor. That’s no one’s fault, of course, and a new pump will be installed next week.

We’re ripping the 1968 sheetrock off the basement ceiling to try and get rid of the dust and debris that is underneath from the renovation, then we can really clean up the boiler.