Best Of

I hate to see shavings coming off the tubing, but to be fair, it happens. I literally take my knife and remove the sharp edges of the hole before pulling it in, but I am paranoid. Those scrapes (unless really severe) will not compromise the strength of the pipe but it is removing a bit of O2 barrier. After system has been in operation for a while it makes dark spots on the tubing evey place the O2 is getting in. The damage to the O2 barrier during install is one reason pex systems still get more O2 into the system than good old copper/steel systems.

As someone who has done floor heat for years, I still do staple up on a typical room on almost all jobs. The bath on the outside corner or the sunroom will get plates. On a typical job I am happy if my design temp is 140* and some jobs it is a good bit higher. You may say 110 would be much better and more efficient! Sure. But seriously, the $1000s that joist trak will cost to add to a whole house will not be recouped in savings for …. what… decades??? If doing plates on a floor with nails, use the extruded style because the tubing snaps in the underside of plate thus the tubing won't be pushed against the old nails.

As others have posted, you must know what all layers the floor consists of. If you take a shot in the dark, expect to miss sooner or later.

If you use HTP , you must grind off any protruding nails thru the subfloor. I use the following grinder and wear eye protection when grinding. You can buy this grinder for peanuts at Harbor Freight stores. Cheaper than a pack of cigarettes in New York city.

https://www.harborfreight.com/5-amp-4-12-in-slide-switch-angle-grinder-58092.html

Here’s the plates that we prefer. 6 screws hold one plate which holds both pipes in a 16” OC joist bay. Single tube plates can be used in small narrow bays.

This is a pretty accurate on-line tool (need to register but free):

https://hvac.betterbuiltnw.com/Account/Login.aspx?ReturnUrl=%2F

The hard part with existing houses is how leaky the place is, there is no easy way to get an accurate handle on this except for a blower door test. Older houses definitely tend to be on the leaky side.

Is the boiler piped primary secondary or with a hydraulic sep? If so you should not need to lock TRVs open to keep flow moving. With all TRVs closed the Alpha will go into an "idle" mode where it barely spins just to get a reference point, around 7W.

Is the Alpha switched on by a relay box? Caleffi ZCR and some others have an exercise switch to run the pump.

The gpm readout is based on power consumption, rpm, and the calculations by in the computer, as I understand it.