thermostatic steam vent valves

t hardy

Does anyone have any experiences good or bad with these?
I have to maintain an older steam system (new boiler), but I find myself "continually" getting calls and "rebalancing" the system / fiddling with a lot of radiator vents in an older house.

Also, what brand? Danfoss? Oventrop? other?
Are there any considerations (vent stuck near wall, etc.).
Thanks much!

nicholas bonham-carter

steam balancing

i would wait on the TRV's until you are certain that you have as much venting as possible on the steam returns, so that you have next to zero back pressure as the mains fill with steam. then put the same size vents on all the rads on a floor [over 2 floors use slightly bigger ones on the top level]. this will come closer to all the risers filling at the same time, without "jumping the gun" while waiting for the air to sqeeeeeeeeze out of constipated little openings. otherwise the risers closer to the boiler will start filling before those at the end, and bingo, a hot spot! don't forget that low pressure helps too [under 12 oz.]--nbc

t hardy

Been there done that. I use hand adjustables at $26+ a pop.
The problem is that the house is rented part of the time - to different sets and types of people - you know the Boston, NY, etc. types. And they control the heat just like they do in their older apartments - they open the window / they fiddle with the gate valves.

nicholas bonham-carter

problem renters

just take the handles off the valves, and crank down the packing nuts. if the thermostat is out of their control and set at 68 deg, or 66 in the coldest area, they will be closing the windows. if you can get every part of the building within a couple of deg. then the tennants will be happy, and so will you.--nbc

mark ransley

Adjustables like dole with tenants are dumb, as you see. TRVs cost near 150 a pop and you Can adjust-bypass the tamper resistant Danfoss, plus they may not work as my new 3 Danfoss dont, yet. They say you need under 2-lb, well im at 1 lb so maybe I have a defective one. Best is balancing the system through accurate measurements with Gortons, they have 5 radiator vent ranges and are 4-5-6-C-D. Start with mains venting. You can also reduce a radiators output by venting at the top hole, not middle. A real cold rad might need a Vari Vent. But first do mains and be sure radiators have an angle for 1 pipe steam for the water to drain back, I had alot of floors done and the guys removed shims and I have had a mess. I just bought 3 Danfoss Trvs to experiment and I think I just wasted 450$. If after its balanced, and top vented [for hot rooms] and a room is to hot you can take a piece of aluminum duct tape and cover the vent hole and use a pin to make a smaller vent hole. Complete balancing is a major job, make one apt cooler and 3 more get hotter, you should get Dans books to learn about steam, you may not even be running efficiently as I found I am not and all the Pros I had really dont know about efficient set ups. Start with a good IR thermometer and calibrated mercurys in every apt, I bought a bunch I could adjust the glass, most all you buy are 1-3f off, calibrate them all the same and record every apt temp, now you have a start point. Balancing is no fun.

t hardy

removing the valve handles is something I hadn't thought of for some reason, you don't really need the dang things - thanks

appreciate your comments - these are bedrooms in a huge old victorian with my customer's customers paying big bucks
Reading your experiences with Danforth is VERY discouraging
Ideally I would want the individuals to be able to adjust the heat themselves. Of course, as you pointed out changing one too dramatically could affect the rest.

I'm pretty good with single pipe steam and venting mains and drain back are good, and balancing isn't really too bad depending on how you do it. (My secret, as I only have one steam customer and he is a very good customer, is to go over at about 2AM on a really cold morning with a pair of shorts, strip to include bare feet and do the final adjustment - one gets a real appreciation of a lot of radiant issues in the bargain. Of course, I only do this once a year before his rental season starts.

Liked your idea of measurement - I have an IR camera as I also do energy audits, so it should be easy.

Dont' know why Danfoss /Oventrop/ other? doesn't chime in here??

nicholas bonham-carter

perfect solution

what good luck that you have an IR camera! you have the ultimate tool!! start the system, and look at how the mains heat up, through your camera. all the returns should heat up quickly. most importantly, look at the risers close to the boiler, and compare their heat rise with that of those at the end of the line--they should be almost identical in "start of rise." this is why the venting needs to produce no back pressure, so that steam is not forced up the first riser from the boiler, so much more quickly than the last riser. the main point is to get the steam to arrive on each floor at the same time, with perhaps the top floor vented amply enough to arrive there first.

while you are at it look for other "envelope" problems.--nbc

t hardy

the other thing to note is that these old victorians are very leaky, so balancing requires a decision on whether the doors on the upper floors are to be kept normally shut or open -
still find it hard to believe that there is only one steamhead out there that has tried the thermostatic valves
and the companies are mum

Mark Eatherton

TRV's should be MANDATORY on steam systems...

IT will provide perfect upper end comfort control. It WON'T address any under heating conditions because it can't send a signal to the steam boiler saying "Hey, we're cold up here..."

But it will provide overheat protection and should automatically balance out the system, assuming the mains are properly vented and drained..

Either brand works fine. USed both, no major problems.

ME

nicholas bonham-carter

companies on the wall

there used to be more input from many companies here, unfortunately, some would have a bad experience from some homeowner over warrenty issues. as a result, very few still identify their presence here--a great shame!

i am not against TRV's, i just have not needed them yet. they are somewhat expensive for my 55 rad system, and all too often, are used to compensate for an undervented [on the mains] system.

why not post some of your IR pictures, to show us what your system looks like, as it heats up?--nbc