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Re: Hoffman 2 Vents?
The argument the dead men make is that open vented all the steam must be delivered against atmospheric pressure so the boiler must generate something over 14.7 psi to get it to move to the radiators. With sub-atmospheric delivery that 14.7 at the header is not needed so obviously the delivery is accomplished with a lot less effort.
I don't have any figures for how much this saves. But I can say for sure it does save. Igor published numbers with a pumped system and the savings was very significant.
But I will say it one more time - the real benefit to vacuum operation is on the comfort side. Radiators stay very noticeably warmer longer between burns which evens things out considerably and natural balancing occurs because radiators in the colder areas pull more of the available steam from the mains between cycles. My upstairs/downstairs difference which was significant (and a pain) disappeared altogether with vacuum operation. Steam returns much faster to the radiators on the next burn because every burn starts with the system at the deepest vacuum. Remember, all this happens every cycle and that adds up to a lot of steam travelling against less resistance mostly to the coldest places (wherever they are today) in real time.
If you haven't experienced this first hand then you really don't know.
One other thing, as Hoffman explained, in a one pipe system just one vacuum vent on one radiator will cause that radiator to pull a greater share of the total system steam than without it. Why? Because at boiler shutdown all the other radiators will instantly cease to pull steam from the main while that one won't stop. It isn't that much each time.....but it is every damn time, and it adds up.
I don't have any figures for how much this saves. But I can say for sure it does save. Igor published numbers with a pumped system and the savings was very significant.
But I will say it one more time - the real benefit to vacuum operation is on the comfort side. Radiators stay very noticeably warmer longer between burns which evens things out considerably and natural balancing occurs because radiators in the colder areas pull more of the available steam from the mains between cycles. My upstairs/downstairs difference which was significant (and a pain) disappeared altogether with vacuum operation. Steam returns much faster to the radiators on the next burn because every burn starts with the system at the deepest vacuum. Remember, all this happens every cycle and that adds up to a lot of steam travelling against less resistance mostly to the coldest places (wherever they are today) in real time.
If you haven't experienced this first hand then you really don't know.
One other thing, as Hoffman explained, in a one pipe system just one vacuum vent on one radiator will cause that radiator to pull a greater share of the total system steam than without it. Why? Because at boiler shutdown all the other radiators will instantly cease to pull steam from the main while that one won't stop. It isn't that much each time.....but it is every damn time, and it adds up.
PMJ
3
Grundfos Ups15-58fc speed switching guts
A while ago (2021) I was working on an air handler project and wanted to be able to switch my pump speed with a relay as part of a two stage air handler heating system. I was trying to keep the boiler in the fully condensing mode by slowing flow in the coil to get a high delta T. This is what I found inside a scrap 15-58 pump I had on hand. Yes, I tested it and the relay switching worked well. I know that most won't care and would never need to such info. Someone might find it useful at some point. NO, I don't think the 26-99 is the same. Obviously, use at your own risk. 
Teemok
1
Re: Cover-Tech Heat Pump Covers
The problem is the use of aluminum coils ... Nice set up...
Big Ed_4
1
Re: Water source heat pump piping
In both of the situations you quote, @WMno57 , there was almost certainly enough ground water movement so that you would be extracting heat primarily from the moving ground water, and not -- strictly speaking -- from the ground. And as we know, moving water is a grand way to move heat around! Particularly if Mother Nature does it for you...
So in those situations, it is likely that having all or part of the heat exchange grid pipes under the house world have worked quite well. Not any better than somewhere else on the property, but not much worse, either.
So in those situations, it is likely that having all or part of the heat exchange grid pipes under the house world have worked quite well. Not any better than somewhere else on the property, but not much worse, either.
Re: shut off valves turn but don't work
You can add a mini ball valve before the vent if this is one pipe steam
No air out = no steam in
No air out = no steam in
dko
4
Re: The case of the backward flow, this Friday's case
Oh wow I was agreeing with earlier post about check valve assuming everything was piped correctly. Never would’ve thought of them stuck closed. Thanks everyone made me think here about things I would have not thought of . I’m still learning things every day
John732
1
Re: The case of the backward flow, this Friday's case
@gerry gill Most welcome sir
@dko They didnt appear to be full of slide. I pushed in with my screwdriver and they were stuck closed
@SgtMaj I learned a lesson that day. Never assume. I get humbled regularly in this industry LOL
@dko They didnt appear to be full of slide. I pushed in with my screwdriver and they were stuck closed
@SgtMaj I learned a lesson that day. Never assume. I get humbled regularly in this industry LOL
Re: Old Toledo 1-A pipe threader
I used to thread pipe 10 hours a day, 5 days a week. Borderline OCD about it and every single one had to be perfect. When I started I compared my results to a domestic factory made nipple and domestic fittings. It is usually 2.5-3 full rotations you can do with just your fingers. I carry only SIAM made imported fittings, and they too are only 2.5-3 rotations. It varies more once you get into the cheaper imports.
Your tool is fine it seems. 4-5 is pretty high, would definitely aim lower. Unless you're talking about full grip hand and going as much as hard as you can without a wrench, but even then I'd want it at most 3.5-4. This also means you are thinning out the pipe that much more at the tip.
I use a ridgid 300 and 1224. Should never follow their guide lines. not accurate whatsoever. I'm always above or below the line a little. I can adjust it maybe 1/16" and its a difference of the nipple going all the way inside a fitting without resistance, only going half a turn, and just right. So your teeth wearing out even a little can make a huge difference.
Your tool is fine it seems. 4-5 is pretty high, would definitely aim lower. Unless you're talking about full grip hand and going as much as hard as you can without a wrench, but even then I'd want it at most 3.5-4. This also means you are thinning out the pipe that much more at the tip.
I use a ridgid 300 and 1224. Should never follow their guide lines. not accurate whatsoever. I'm always above or below the line a little. I can adjust it maybe 1/16" and its a difference of the nipple going all the way inside a fitting without resistance, only going half a turn, and just right. So your teeth wearing out even a little can make a huge difference.
dko
2
Re: NEST With Two Wires
If anyone is interested, I believe the NEST uses a circuit basically like this to switch the R and W wires. N-Channel Mosfet Transistor. Very low trigger current compared to a coil of a relay or a TRIAC.
The NEST version is probably more complex since they may use the transistors to multiplex commands to the Nest Power Connector when used.
The NEST version is probably more complex since they may use the transistors to multiplex commands to the Nest Power Connector when used.
109A_5
2