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TRV Guide

Read this article in the digital edition.


As the heating season approaches, many of us are preparing for another eight months of ridiculous overheating in our apartments. Despite all the concern about being “green” that is supposedly sweeping New York, you wouldn’t know it from the sauna-like conditions New Yorkers have come to expect but feel powerless to change.

It doesn’t have to be that way. There’s a technology out there that is about 50 years old. Few seem to know about it, and it can cut overheating and fuel bills to fairly low cost. It’s called a thermostatic radiator valve (TRV).

TRVs have been popular in Europe for decades, and they’ve made some inroads here in the United States, but they remain largely unfamiliar to most co-op dwellers. In order to raise the profile of TRVs, a prominent manufacturer sponsored a small demonstration project last winter in two buildings on the Upper West Side of Manhattan.

Danfoss, a Danish manufacturer of a wide range of heating controls, hired Power Concepts, a Manhattan engineering firm, to monitor the results of a building-wide TRV installation at two sites – one with a one-pipe steam heating system, the other with a two-pipe system.

I worked at Power Concepts at the time and oversaw the project. Our team learned a tremendous amount about what to do – and what not to do – when installing and using these valves. What we found could be very useful to any building that wishes to adopt this technology.

Installation – Easy as 1-2-3-4

A typical TRV costs roughly $100, but installation labor can run up both the cost and the payback period. For this reason, we concluded that in-house installation, if at all possible, was the most cost-effective approach.

If you have a one-pipe steam system, in-house installation should be a breeze. The TRV replaces the air vent on the radiator and can be installed by any reasonably handy person in about five minutes (fifteen minutes if the TRV requires a remote temperature sensor).

Two-pipe systems present a greater challenge, and it is here where many buildings falter. They ask a plumber for a price quote and are scared away almost immediately by the cost. Fortunately, the super in the two-pipe “test” building was more than willing to tackle the installation, and he and his assistant did an excellent job. Despite never having seen a TRV before, they installed nearly 200 in about three weeks.

But they did run into a few issues, most notably a need to temporarily disconnect some of the radiators at both ends, which was unusual and unanticipated. Some of the existing radiator covers required small cutouts to accommodate the TRV as well.

For another two-pipe system unrelated to the project, Danfoss developed a “drop-in” replacement cartridge suitable for Dunham-Bush orifice-type radiator valves, commonly found in many New York buildings. This reduces installation labor dramatically and virtually eliminates the need for a plumber, because no pipes have to be touched (unfortunately, the two-pipe building in the project did not have this option).

By the way, it’s critical in one-pipe buildings without a Heat-Timer or one of its clones that the boiler control periodically (hourly, say) shut off the boiler long enough to allow steam pressure to drop essentially to zero.

Caution: Human Beings Involved

The project was intended to be as rigorous as possible, given that there were many factors outside our control – like the supers and the tenants, for example. We tried to minimize human error by sending a brief letter to each apartment describing the nature of TRVs and of the project, and by discussing with the supers in some detail what should and should not be done, especially in response to tenant complaints.

This being New York, many people didn’t read the letter, lost it, or viewed it with suspicion. And many people simply did not like the idea of TRVs, period. As a result, any time anything went wrong with the heating system, it was blamed on the TRVs, even when a causal effect was physically impossible.

Thus it was that one Saturday evening while dining out of town with friends I received a semi-panicked phone call from a board member of the one-pipe building. Almost everyone in the building was complaining that they were burning up from overheating.

Now I knew this could not be the fault of the TRVs; they can reduce overheating, but they can’t create it. But I had no idea what was going on, and so I reluctantly agreed to let the super turn down the Heat-Timer. When I returned to the city and heard the full story, I was incensed – the super, contrary to our specific request, had adjusted the Heat-Timer in response to a “no heat” complaint and had not told anyone.

That in and of itself might not have been so bad, but the super had made a big boo-boo: he had adjusted the “XYZ” knob on the Heat-Timer, not the usual knob, so that the boiler basically ran continuously no matter how hot or cold the outdoor temperature. This was but one example of a number of similar issues, large and small, in both buildings, all of which made it difficult for the TRVs to do their job.

Energy Savings, Etc.

When the heating season ended, we analyzed fuel consumption data and concluded that the one-pipe building saved about four percent and the two-pipe building about nine percent of its fuel, for a simple payback of

about 3 years. We made the following additional observations:

Most of the two-pipe residents liked the TRVs and found that their apartments were significantly more comfortable.

Many of the one-pipe residents liked the TRVs, but some folks still blamed them for problems the TRVs could not possibly have created.

The one-pipe building changed Heat-Timers in mid-March and thereafter experienced significantly elevated apartment temperatures.

The “vacuum breaker” on a few of the one-pipe TRVs stopped working because of debris inside the heating system; this clogging may have affected the TRVs’ operation enough to result in overheating.

Teething problems notwithstanding, we judged the project a success. Overall comfort increased, and energy consumption decreased, in both buildings. We believe moresavings are possible as shareholders become more familiar with these devices. We also believe that the TRVs will permit adjustments to the Heat-Timer that will

result in additional savings.

If you are considering installing TRVs, note the following: 1. Develop in advance as much support for the project as possible. Provide an information session for all interested parties so everyone will know what to expect.

2. Have a knowledgeable expert oversee the job.

3. Use in-house installation labor whenever possible.

4. Develop a specific protocol for dealing with “no heat” complaints wherein turning up the heating control is the absolute last resort.

5. Be patient. It may take a few months for everyone in the building to be comfortable with these new devices.

6. Once the shakedown period (which, as mentioned above, could be a few months) is over, experiment with adjustments to the boiler control to gain even more savings.

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