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Herb Member Posts: 31
We have a Weil-Mclain Gold (GV-4 Series 1) boiler that starts a heating sequence , goes through the normal steps , fires up and then starts to gradually lose pressure on the air switch. Once the pressure gets low enough to drop the switch out the unit goes into lock- out. What's causing the combustion blower to do this? We have replaced the air switch and checked the tubing, but the condition persists.


  • Doug Wagoner
    Doug Wagoner Member Posts: 78

    My 3 year old GV-4 did the same this winter also. When I traced the problem to the air pressure switch I found water in the tubings and the switch diaphram. I shook this out, cleared the lines and reassembled still thinking the switch was failing. The boiler functioned normally the rest of the night but I ordered a new pressure switch next day to be on the safe side. I have not yet installed it. That was a month back.
  • Bryan_16
    Bryan_16 Member Posts: 262

    The GV boilers will sometimes rust shut from the inside out. You can also check to see if there are leaves or other restriction in burner cone. I have seen this problem with Series 1 boilers before. Unfourtunately, end up changing the boiler. W-M does a good job of taking care of the warranty. Call a pro.
  • Mark A. Custis
    Mark A. Custis Member Posts: 247

    putting a monomitor of some sort with a "T" in line between the hair dryer thing (inducer assembly) and the pressure switch to see what is really going on. To find out more add a clamp on amp meter to the line voltage side of the inducer motor.

    My guess from beautiful downtown Sheffield Lake Ohio, is either the inducer motor is getting old, or there maybe a bit of rust building up in the barb connector. I'll bet the pressure switch is fine. You can check that too with the monometor. Leave the "T" attached and with a multimeter in olms or tunes, suck on the tubing and see at what pressures the switch makes and brakes.

    Good luck,


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  • Floyd
    Floyd Member Posts: 429
    Check for water in the exhaust....

    the little line that drains the exhaust pipe gets loaded with sh..... and only lets a little water get through......
    the water builds up.... shuts the boiler down....by the time you reset it the water has drained out, so it works for a short time again..... pull the tube off and dump it out and you will be a happy camper again.

  • Dan m_2
    Dan m_2 Member Posts: 15

    I had a 6 year old Gv5 start shutting down a couple of winters ago also . I kept it running for the last few weeks of the heating season by jumpering the vacum sensors ( very difficult to find a seasoned boiler man in my area). It acted like the exhaust was blocked but it wasn't The following year I got a free GV5 from Weil when the six year old version died. The local scorched air guy ( who i now beleive is defending Bagdad) stuck me with a $1700 install bill for cutting a couple of pipes and hooking the new one up. Not that this helps you any but like a alcoholic needs to talk , somtimes it helps people that have been hosed by a "Pro" to talk out their pain.Their are alot of great guys on this sight that know their stuff , but unfortunatly thier are a lot of people that have tied a ladder on their truck and talk the talk , walk the walk. Just go to a dinner party or other gathering and bring up home repair horror stories and listen , everyone seems to have them.
  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    Hi ya Dan

    Just make sure you're not getting condensate from that drain. Hope to talk to you soon about changing that piping around a bit. Glad I saw your post.

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