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I have a honeywell PA404A pressure control switch on my home gas steam heating system. I'm having a problem with the switch turning off the system. It will only come back on if I turn the top screw all the way out, then back down to approx 5psi. At this point the heat will turn on but when the thermostat shuts down the system it will not turn back on when calling for heat unless I adjust the screw again. Also, the switch will only turn on the system when set at 5 on the dial on the inside. Any ideas? Thanks, Crai

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This may be caused by accumulation of sludge in the steam trap (the looped tube that connects the pressuretrol unit to the boiler). the sludge restricts the pressure from reaching the diaphragm in the pressuretrol unit. So it gets a false reading. Clean or replace the tube and see if normal function resumes.

Posted on Dec 07, 2009

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Here's a link that may help it explains the controller and how it works. I personnally would not be adjusting this control as you have been because its a safety that shut off the unit in a unsafe condition. If it's malfunctioning then thaat is when you need to call a service company to check out why. You would not want your unitto explode because of a high pressure condition. Please have your unit serviced.

Posted on Jan 06, 2009


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Posted on Jan 02, 2017

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I have just bled my radiators and the pressure has dropped dramatically on my Honeywell cm721 boiler the blue light has gone out. I have switched it off. What should I do

Honeywell cm721 isnt a boiler, that's the tstat. You should have 15#s pressure on gauge. If it is steam you should have 2#s pressure. Not knowing what you have, I would start with checking these gauges. Unit may be off on low water.

Nov 01, 2017 | Honeywell Heating & Cooling


Hot Water Steam Efficiency Plus Comfort

Steam heat is a great warm, wonderful, and absolutely fabulous way to heat your house. Steam heat is almost always created from water in a boiler fueled by gas, oil or electricity. It then passes through pipes and radiators or convectors to heat your home. A steam heating system uses steam that is generated from a boiler. When the water boils, the steam rises through the pipes and into the radiators to heat them. The hot radiators then heat your home.

Steam is a great heat distribution medium because it moves easily through your system and it has an extremely high heat-holding capacity. The heat-holding capacity of steam is much greater than that of water. Steam heating systems often operate at very low pressures and usually under 220°F. Steam heat is usually distributed by either one or two pipe systems. In a case of a one-pipe steam heating system, a single main serves the dual purpose of supplying steam to the heat exchanger and allowing condensate to run back from the radiators also. A two-pipe system has two connections from each heat exchanger or radiator. In this system, steam and condensate flow in separate piping from each other. With a steam system all pipes must be well insulated and you must use pipe insulation rated for steam piping. If the insulation is removed the system will no longer work as designed. Noise and all sorts of problems will come from uninsulated piping.

When you have radiators on upper floors or radiators that are further from the boiler they should be adjusted to release more air to compensate for the increased air volume in the piping due to the distance from the boiler. If you have a valve that is clogged with mineral deposits or stuck shut, no air will be able to get out of the piping. Because of this no steam can enter the radiator, so it doesn't heat up. This will block the movement of steam into the radiator, or cause a very noisy hammering as pressurized steam tries to get through this water "dam".

Steam radiators need to have a valve that allows air to escape at a controlled rate so that the radiator can heat up. Steam heating systems will also lose a little bit of water all the time, so there has to be water makeup so that you do not run your boiler dry. Steam heating systems without an automatic water feeder are not safe. You will risk serious boiler damage should boiler water be lost. If the boiler runs dry it could also explode if water is placed into it while it is hot. There should always be a low water cutoff installed on every steam system. Therefore on a steam boiler the automatic water feeder serves as a safety device also.

It is very important that you find someone that is very familiar with steam heating systems when repairing or installing steam heating. Incorrectly designed, installed, steam systems and condensate piping is a huge problem in today's buildings and facilities. There are not many qualified to design and install properly operating steam heating systems. Incorrect steam piping will always cause costly premature failure of steam equipment such as steam coils, heat exchangers, and control valves. Not to mention the higher cost of operating a system that is not working efficiently.

on Dec 29, 2009 | Heating & Cooling

1 Answer

My Honeywell Water Heater Thermostat will turn on for 30 seconds. Then it shuts down- wait 5 seconds turn it off EITHER with the ON/OFF switch OR by turning thermostat to off & back on immediately! If...

Time to call qualified service technician. And watch what that person does to learn about your water heater.
I assume you have Honeywell Icon gas valve. Honeywell makes different several model numbers.

Here is 'typical' Honeywell Icon gas valve service manual for Bradford White, that may or may not apply to your water heater. It shows testing for Icon and disassembly instructions, and error codes.

Gas water heaters today require yearly service that includes cleaning burner parts and combustion chamber, checking vent and air intake, electrical connections, testing gas valve, checking gas pressure, bleeding air out of gas line, etc. These are things you can learn to do by reading service manual, and making sure you have a spare water heater around to connect real quick if experiment goes wrong.
If Icon gas valve is problem, that control is modular and can be replaced without draining tank.

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check to make sure there is a jumper wire on the subase between "rc" and "rh". these designations stand for red/cooling and red/heating.they are used independently if the system has a separate control transformer for heating and a separate one for cooling. they need to be jumpered when one transformer is used to control both modes. your fan "on" switch won't work the fan continuosly if there is no connection to the "r/c" trminal.
on the back of the thermostat there should be a switch you need to select for gas or electric heat. or there are small micro switches that need to be set for your particular application.check your installation papers for details.
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Type Honeywell 63-4038 in your search on home page. Select the link that starts with and your model #

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Furnace will not heat.

Most of the Lennox G-16s that I have repaired were having problems with the gray Penn-Johnson Piggyback igniton control module.
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Jan 13, 2009 | Honeywell Electronic Programmable...

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