Getting to Know the Radiators

When I lived in an apartment that had radiator heat, none of the valves worked very well, so we regulated the temperature by opening windows. Now that I’m paying the heating bill, this method of climate control is much less appealing to me.

As I’ve mentioned before, our radiators are hot water radiators, not the more common steam radiators.

Steam radiators use a single pipe that delivers steam up to the radiators and allows the condensed water to drip downward back to the boiler where it’s heated up again. Steam radiator valves pretty much have to be either all the way open or all the way closed, and the amount of steam allowed into the radiator is controlled by a regulator that’s typically on the top of the radiator opposite to the end where the valve is.

Hot water radiators use a one-pipe closed system, and each radiator taps into one or more main ‘loops’ by means of diverter ‘tees’. These tees are called Monoflo Tees, and they have a mechanism inside that restricts the flow of water, causing some of the water in the main loop to go into the radiator, and the rest of it to continue on in the loop.

There are a few really nice things about a hot water radiator system:

  • It’s exceptionally quiet. There’s no banging and clanging like steam radiators make.
  • The radiators are full of hot water, so even after the system kicks off, the hot water in the radiators keeps giving off heat.

The downside to a hot water system is that if you need to replace a valve or a radiator, you need to turn off the boiler and drain the entire system, make your repairs, the refill the system and bleed all the radiators. As I found out, this is an extremely time-consuming thing to do.

Anyway.

Since a few of the radiator valves are frozen, and one is, ahem, broken, our nephew S., who does HVAC work for a living, came over today to replace the radiator valves that don’t work right.

He started off by hooking a hose to the spigot next to the boiler and opened the spigot, draining the system into one of the basement drains. Then he opened the bleeder valves on two radiators upstairs to allow air into the system so that it could drain fully. To my surprise, this took about an hour–I had really expected it to drain more quickly.

We then went to work removing the broken valves. S. had some pretty big pipe wrenches he used to get the valves off. The first three were pretty easy, but the last radiator’s valve was wedged between the radiator and the wall, so we had to unhook the radiator from both ends and move it aside. I’m really glad that this was the smallest radiator in the house, because it took just about all our strength (and S. is a big guy) to move it. I’d guesstimate it weighed about 200 pounds.

We needed to replace two 3/4″ valves and two 1/2″ valves, so we went to Home Depot where we got the first two valves, plus some “pipe dope” (compound to use when joining steel pipe) and teflon tape. We had to visit two different plumbing supply houses before finding the 1/2″ valves, but S. knew right where to go.

We got the first three valves on without too much trouble, but the other dining room radiator had a slightly offsized nut and a slightly oversized nipple, so instead of heading out to buy a radiator wrench, I cleaned and lubed one of the old 1/2″ valves and just replaced it.

Then S. started refilling the system, and we bled the air from each radiator. Then we turned the system back on, gave it a bit of time to heat up, and bled the remaining air from the radiators.

It was 62 degrees inside when we turned the system back on, and in less than two hours, the house was up to 71 degrees–it felt downright balmy.

M. spent two grueling hours in the basement scrubbing accumulated years of filth and crap out of the radiator covers, and S. and I put them back into place, so we should have a nice warm house this winter.

One Response to “Getting to Know the Radiators”

  1. Chad Whiteman Says:

    Hi,
    Was looking for some info on maintenance of my hot water radiator heating system for my home and came across your blog. I have a few radiator valves that are froozen as well. I haven’t tried putting a pipe wrench to them yet to see if they would loosen up for fear that they would break. But, I plan to try something before winter comes around.
    I don’t know if you have time to answer and questions or not, but I had a few. How much torque can you put on the values before they break? What type of valves did you use?
    Thanks,
    Chad

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