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Re: HTP Boiler short cycle
It has honestly acted like this intermittently since install in 2017.When the boiler was originally designed and initially delivered in 2015, it had serious issues with the control logic. The boiler could not modulate quickly enough before it reached +5F. over limit. Then it would shutdown on limit and restart about one minute later.
HTP made several iterations of that control over the two years between 2015 and 2017.
When done, the boiler could respond properly to an instantaneous closure of two zones (out of a total of three) and it would NOT shutdown on limit. HTP decreased the response time for modulation and also increased the the margin to +12F over setpoint before a shutdown occurred.
The final result was truly excellent from the original starting point.
Sadly, most installations of this boiler in that time frame will suffer from the poor control logic and none of the installers can do much about it.
You can mitigate the issue to some degree by reducing the CH heating capacity. This is parameter 18:cb on the display. If you can heat the building with 40K BTU's (likely) set the parameter at 55. It's much easier for the boiler to modulate down from 40K then from it's maximum (72K). Step modulation (37:CM) will not help with this issue.
However, understand that this approach will severely limit your capability of recovery if you are inclined to reduce the building temperature overnight.
If you were to replace the control board, all issues would disappear.
LRCCBJ
2
Re: Two Pipe radiator plumbed in after the vent on the return
@Ted_Ryan
If it works ok and it likely will there is no need to relocate the vent. If you have a problem just stick a vent on the radiator return close to where it ties into the main return.
If it works ok and it likely will there is no need to relocate the vent. If you have a problem just stick a vent on the radiator return close to where it ties into the main return.
Re: Plumbing archaeology
Plumbarius...worker of lead. No, drum traps are prohibited in New installs. Mad Dog 🐕
Re: Hot water vent (!!) on steam main
It just won't work righ. It won't hurt anything except it will cause the system to not work as well as it should. Post some pictures of the system, a couple of radiators and a few boiler pictures including the boiler piping.
Re: Hot water vent (!!) on steam main
The wrong air vent will either prevent air from escaping the system impeding the flow of steam leading to longer heating cycles to satisfy the thermostat in addition to building pressure which may be sufficient to trip the pressuretrol leading to short cycling of the boiler. If the pressuretrol doesn't work due to a clogged siphon loop (pigtail) or is set to too high of a cut-out pressure the built up pressure may damage the air vents on the radiators. Higher pressures lead to wet steam from the density of the steam being forced out of the boiler which may cause the water line in the boiler to drop lower than usual.
If the air vent leaks there will be a drop in the water level in the boiler over time which can lead to various problems; most commonly excessive make up water being added.
The better your main air vents are the more efficiently and quietly the system will run. Steam needs air out of the way in the pipes to get to where it wants to go and good vents will also keep steam trapped in the pipes so that you don't lose water.
If the air vent leaks there will be a drop in the water level in the boiler over time which can lead to various problems; most commonly excessive make up water being added.
The better your main air vents are the more efficiently and quietly the system will run. Steam needs air out of the way in the pipes to get to where it wants to go and good vents will also keep steam trapped in the pipes so that you don't lose water.
Waher
1
Re: Two quotes for combi boilers for radiant and DHW
Nothing to lose by adding some pressure. Below 30 psi.You increase pressure by lifting this metal hoop on the pressure reducing valve. It basically allow the pressure in the building to bypass that valve, so lift it carefully as you watch the pressure.
Download the manual for more operatinginfo.
So I should try to build pressure up to 25 psi (by lifting metal hoop on pressure reducing valve) and then seeing if pressure drops? Because the reducing valve seems to be set around 11 psi, I assume no new water will enter system until it gets to around 11 psi?
hot_rod
1
Re: Two pipe steam radiator problems!
I bet it's just hot condensate from the steam main, dropping into the wet return.Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.
So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time? Does it get hot before the return backfills ?
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?
Re: Two pipe steam radiator problems!
I concurSteamhead said:I bet it's just hot condensate from the steam main, dropping into the wet return.So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.
and what of the wet return at this time? Does it get hot before the return backfills ?
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?
reggi
2
Re: Two pipe steam radiator problems!
I concur also...I bet it's just hot condensate from the steam main, dropping into the wet return.Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.
So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time? Does it get hot before the return backfills ?
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?
Re: HTP Boiler short cycle
it is in the manualjoncroteau said:It hasn’t ever. I’m setting that up with my local hvac company. The boiler also throws ‘no ignition’ codes so I will have them check the pressure as well.mattmia2 said:when was it last checked with a combustion analyzer?Any idea what the normal parameters of the combustion test would be?mattmia2 said:when was it last checked with a combustion analyzer?
it must be set up with a combustion analyzer when it is installed. if the combustion isn't adjusted right it is likely to not ignite sometimes. if it has been running for years like that it likely needs soot cleaned out of it too
mattmia2
2