Seeking feedback on new TRV

ChrisJ

MaidOMist1932 said:

Nick_Castrads said:

@mike212 thanks for your comments. We have to choose one or the other for mass purchasing of the packaging so we've decided to go with the vent, but it'll be a similar price to those sold without.

Hey Nick. I really appreciate the shout out to Maid O' Mist on this thread. I work for the company and recently created this MOM account. I believe there's a possibility that we could plate the Jacobus Vent to match the TRV. I'd like to chat with you on the idea. I also really appreciate others on this chain mentioning our ye olde company. FYI - we are rare breed these days, one of the very few manufacturing vents in the USA, Arlington Heights, IL to be exact. I can be reached at brian@maidmist.com. Thank you.

Thank you for posting here.
IMO when manufacturers and distributors show a presence here, it's a big deal. It means a lot to us.

MaidOMist1932

You're certainly welcome. Thank you.

Bob_127

Are you going to have an option for an external temp sensor for radiators that have covers?

Sylvain

GregM said:

My biggest "usability" gripe is the numbering system, 1 - 5 etc. If it's possible, having that dial in "max degrees F / C" would be a big help for others in my family. Happy to try them out if you need more beta testers!

EdThe HeaterMan had a good story about how he choose the temp of his air conditionner for the summer.
He started at a recommended low temperature but then the bill was rather high; so he raised the temperature each day until his daughter asked if the AC had failed. Then he came back one step.

Trying to achieve a known temperature might not be the best idea.
Trial and error seems better. After all if it is comfortable, that is what is important.

Any way, comfort depends on clothing, physical activity and so on. It might change during the day.
And if various people are in a room, maximum 95% of them will be satisfied.

ChrisJ

@Sylvain

The other issue, besides the wax motor design (Which is incredibly reliable, by the way) is the fact these get mounted by a cold outside wall, often under a window.

The point being in one room you may want it set to 70F to achieve 72F in a room but in another it may need to be set to 62F for similar results.

dko

Is the goal of this TRV to be a competitor in the market or simply a better companion for your Castrads?

As in, will this TRV be in the supply chain distribution or just on the Castrad website when purchasing a radiator?

Waher

I would be very interested to try one of these. 

fastd

Hi Nick,
Your valve sounds very interesting. At the moment I have no place to test them, so would not request samples. However, would appreciate you keeping me in the loop on product info. my email: dan.fast42@gmail.com

Dave Mc

Hello Nick, I Would love to sample your new product and provide feedback.
I have a 5 bedroom 3 story in central PA with a single pipe steam system. I've been considering trying TRV's to regulate the rooms- as their occupancy varies from time to time, and it seems a better option than completely closing the rads. Thanks.
DaveMc@mail.com

Nick_Castrads

@JoeEngineer thanks for your interest. I've logged your email, will be in touch with more information ASAP.

Nick_Castrads

@Steve10 appreciate your interest. I'll reach out for your email via DM. Word of warning: as with all TRVs, ours won't work if the pressure is set too high and you're not able to convince the super to crank it down.

The passage below is from a DoE paper titled Thermostatic Radiator Valve Evaluation written by Jordan Dentz and Eric Ansanelli, published in Janaury 2015.

I appreciate everyone on this forum already knows this, and @DanHolohan has been saying this for decades, but overly high pressure systems remain our single biggest reason for TRVs not working as expected.

4.1.3 Boiler Control Set Points
Boiler operating pressure and outdoor reset curve settings could affect both the ability of TRVs
to control individual radiator heat output and the building-wide effect of TRVs on heating fuel
usage. Although the TRV manufacturer’s recommended limit for operating steam pressure was 2
psi above atmospheric pressure, the steam boiler in this study was set to operate at a range of 2–5
psi. Neglecting for pressure drops along the steam mains and risers, 5 psi at a radiator would
compress the trapped air volume by approximately 25% and, therefore, allow that radiator to
emit 25% of its maximum heat output, even when the TRV has successfully closed. If the
operating pressure could be reduced to a maximum of 2 psi, this would allow only 12% of the
radiator to fill with steam in the same case, increasing the ability of the TRV to limit radiator
heat output.
Pressure and volume of a gas in a vessel share the relationship:
Vnnn = Vooo × Pooo ÷ Pnnn

In the case of 5 psi of steam pressure at the radiator, this would compress the trapped radiator air
to a percentage of its original volume:

1 × 14.7 ÷ (14.7 + 5) = 75%

In the case of 2 psi of steam pressure at the radiator, this would compress the trapped radiator air
to:

1 × 14.7 ÷ (14.7 + 2) = 88%

The TRVs used in this study were built to withstand up to 15 psi without risk of mechanical
failure. (This refers to the close-off pressure of the valve. Of course, 15 psi as an operating range
for the steam system would be grossly inappropriate for the reasons discussed above.)

Nick_Castrads

@MaidOMist1932 thanks for the post - that souns really exciting. Thanks also your email, will respond momentarily.

Nick_Castrads

@Controlsgirl thanks for the offer! My email is nick@castrads.com - feel free to drop me a line or I'll DM you to get your details.

Nick_Castrads

@ChrisJ I think it's pretty sexy. What do you think?

Nick_Castrads

@Bob_127 I'm afraid we don't have any plans to add a remote sensor for the moment.

Nick_Castrads

@dko primarily we wanted to improve on our existing offering which was a design we made early on in our steam heat career. In particular, our current TRV lacks an inbuilt vacuum breaker (instead we add a ½" VB to our radiators), but as @Waher has mentioned this isn't ideal for retrofit to existing radiators.

We're hoping to sell this TRV for both our own new radiators and for use as an easy-to-install retrofit valve to improve comfort in any one-pipe home, rented or not, where design is a consideration.

Functionally, it's (I hope) at least on a par with Danfoss, but we'll offer four finishes and - as @ChrisJ has said - hopefully it's a little more glamorous than the current best in class.

The price point will be similar to Danfoss's TRV, but ours will also include the Maid o' Mist vent within the price. It'll also be sold as a single-piece construction so that there's no assembly at home (except adding the vent).

Nick_Castrads

@Waher That's great news, I'm really glad to hear it. Will add you to the list.

Nick_Castrads

@Dave Mc thanks for your interest, I've added your email to the list. Sounds like these TRVs should do just the job.

Sylvain

Nick_Castrads said:

[..] Word of warning: as with all TRVs, ours won't work if the pressure is set too high and you're not able to convince the super to crank it down.

The passage below is from a DoE paper titled Thermostatic Radiator Valve Evaluation written by Jordan Dentz and Eric Ansanelli, published in Janaury 2015.
[...]
4.1.3 Boiler Control Set Points
Boiler operating pressure and outdoor reset curve settings could affect both the ability of TRVs
to control individual radiator heat output and the building-wide effect of TRVs on heating fuel
usage. [...]

I had to read this 3 times to understand what it was trying to convey.

In other words, if the vent is closed (by the TRV) the air in the radiator will be compressed by the steam generated by the next firing cycle leaving some place for that steam.
If the pressure is 5psi, the place left for steam is 25% (100-75) of the radiator volume, giving some heat to the room.
If the pressure is 2 psi, the place left for steam is 12% (100-88) of the radiator volume, giving less heat to the room and so the TRV is better able to limit the radiator output.

Although, it is not the volume but the area of the part of the radiator filled with steam which will drive the output; so the output difference is not simply the steam volume difference.

The lower radiator heat output [edited] is of course particularly useful when the call for heat is low (mild outside temperature).
Lowering the pressure further would make a greater difference.

Nick_Castrads

@Sylvain You raise a very good point. I like the way Dan puts it personally - crank it down.

DavidK_2

Hi Dan, thanks for being here, and for making this place, and your books.

I've learned to love single pipe steam heat.

I also love being retired.

DanHolohan

Thanks, David!

Nick_Castrads

Thank you to everyone that's sent me emails, messages and replied on this forum. I really appreciate your help. We've made a list of everyone that's expressed interest in trialling the TRV and we'll be in touch again as soon as we have the first valves to send out.

You'll all be glad to know the packaging will include the air vent and we're working with Maid o' Mist on a brass version of their vent for the brass TRV finishes.

In the meantime, I've attached the draft instructions as a PDF. Any comments very gratefully received. Do they cover the main points? Are the specifics correct?

With thanks in advance
Nick

** Update 9:10am - corrected the PDF to our latest version with amendments to some text and the teflon application diagrams.

ChrisJ

@Nick_Castrads

The only thing I'd add is that TRV's aren't just ON/OFF devices.
They can also throttle the air flow and cause a radiator to heat slower than normal as well. For example, causing a #6 vent to behave like a #5 and then slowing down to a #4 as the room heats before closing completely.

I don't know if that information is actually important in the instructions or not.

Nick_Castrads

Thanks @ChrisJ. How about this in the "How TRVs Work" section?

1. TRV responds to the ambient temperature, slowing down or completely closing the air escape route, which slows or prevents steam from entering the radiator.
2. TRV remains closed for the time that the room is at temperature, then opens again when the room cools.

dko

While either is fine, no mention of dope leads those who would need the instructions to assume it's not an approved option. Most commonly available ptfe tape is 1/2" in width which is already too wide for 1/8" threads if they don't fold it in. Maybe mentioning not to cover the first couple of threads and adding in "ptfe OR pipe dope." And then mentioning to use appropriate amount of dope..

And the valve sizing chart, people will use as a guideline to what is "correct" just like the Gorton valve sizing chart. Oh, 3rd floor - size D! When a #4 could potentially be correct. Maybe a disclaimer stating example only and balancing could be trial and error or whatnot.

But I suppose you have to draw a line somewhere otherwise you have to add in an entire training course into the instructions.

Waher

Directions for applying teflon tape clockwise with the threads may be helpful to homeowners that aren’t familiar with its use. The illustration to me looks like the tape is being applied counterclockwise.

Cautioning that if the radiator valve cannot shut off, switching off the thermostat or boiler is necessary for safety. Ditto for a warning that radiators may be hot and not to attempt installation until cooled. 

Maybe have an absolutely clueless person attempt an installation and note every question or difficulty they come up with.

Nick_Castrads

@dko thanks for the suggestion. How about this in the current "Valve Sizing" section?

1. Change title to "Vent Sizing"
2. Change text to "We supply Maid O’ Mist Jacobus air vents with our TRVs, including an orifice pack with 5 different gauges. The correct size depends on the radiator’s distance from the boiler and risers. The diagram above is an example but may not be applicable for every system."

@dko and @Waher, thanks for your input on teflon tape.

How about, in Steps 3 & 5, we change the wording to:
" Add PTFE or pipe dope to the threads (not supplied)..." ?

@Waher re the thread direction: thanks - in fact I've uploaded an incorrect version and we have already corrected the direction of application for the PTFE. Will edit my original post to include the correct version.

Sylvain

Some suggestions

- step 3: add an arrow to indicate how to wrap the teflon tape;
- step 5: idem;
- step 6: replace the word "valve" by "air vent";
- picture 7: add "Wait always several hours between successive adjustments"
- picture 8: is it windosr or windsor ?
- pictures 8 and 9: does the air vent come with an explanation where (and why) to put one of those "air vent orifice"?
- picture 10 title it "vent orifice sizing". text: "The correct orifice size depends on the radiator’s distance from the boiler and risers." Maybe add "Too big an orifice might not allow enough time for the TRV to react".
- picture 11 the word air is missing "1. Steam enters the radiator and forces air out through the vent." Use the same wording for the two "1." sentences.
- picture 12: It won't provide comfort if the boiler is not cycling regularly. Replace psi by psig in the text? Isn't the text redondant?

dko

Actually don't think you should even bother with the ptfe diagram or explaining how to make a threaded connection. Looking at most other brand instructions attached.. none really try to teach you the basics of plumbing. If DIY, that's on you to know. Don't think you need to be training in the instructions. Just straight-forward information like proper location, orientation, operating info, and maid-o-mist sizing info.

Nick_Castrads

@Sylvain thank you so much - this is really helpful. See attached. I haven't been able to add the arrow for the PTFE tape - which we will do, great suggestion - but for now I've updated the text.

Nick_Castrads

@dko I see your point and I agree, however I worry that if we don't explicitly say about the PTFE then it'll come back to bite us.

CLamb

If this is oriented towards the DIY homeowner then you need to tell them to turn the radiator back on and check for leaks.

Nick_Castrads

@CLamb that's a really excellent point that I hadn't considered at all. Thank you. Adding it in now.

Long Beach Ed

Nick, your diagram of the gauge highlights 2 to 3 lbs. The text refers to"over 1.5 lbs". Why is 2 to 3 highlighted?

- Ed

Nick_Castrads

@Long Beach Ed very good question. Will amend to over 2psig.