Oil burner heats water; does not provide baseboard heat

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  #1  
Old 04-30-16, 04:35 AM
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Oil burner heats water; does not provide baseboard heat

My Weil-McLain boiler comes on to provide hot water (coil in boiler), but does not respond to calls for heat from any of four zones. I probably can't make this repair myself (unless it is something very simple) but would like to have an understanding of what might be wrong before the repair person arrives.
It could help me to know the sequence of events once the thermostat calls for heat, i.e., the zone valve opens, then the pump starts, aquastat turns on boiler as needed. It does not seem the zone valves are doing anything. Any advice appreciated. I have an electrical tester. Thanks.
 
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Old 04-30-16, 05:24 AM
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update from original poster

I am not getting any reading at the valves from the transformer. Should be 12 or 18 dc volts I believe (?).
 
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Old 04-30-16, 05:29 AM
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You are close 20 - 30 Vac. If none of the zone valves are operating sounds like you could be right.
 
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Old 04-30-16, 08:48 AM
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Update #2 from original poster

Tested transformer at AC, working ok at about 27v. So now thinking faulty circulating pump; would zone valves not open if pump doesn't work?
 
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Old 04-30-16, 08:24 PM
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No zone valves send a signal to the aquastat to fire the boiler and the aquastat will start the circulator. The thermostat will open zone valve, the zone valve closes an end switch and starts the aquastat and the aquastat will start the burner and circulator.
What type zone valves do you have?
 
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Old 05-01-16, 08:11 AM
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Missing from the quote is that zones are usually controlled either with valves or pumps. With valves there is usually one per zone a minimum of one pump. Typically each thermostat controls one zone/valve. When a valve opens the end switch starts a circulator. Only zones with open valves get flow.

Except in cold start systems, the boiler aquastat operates independently of the zones. When heat removed by water circulating in zones lowers boiler water temperature enough aquastat starts burner, regardless of whether a thermostat is calling for heat.
 

Last edited by doughess; 05-01-16 at 09:32 AM.
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Old 05-01-16, 08:24 AM
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With a four zone system there may be more than one transformer. If you have the typical three terminal zone valves..... you should be reading some AC voltage on them.

If you're stuck.... shoot and post a few pictures of the wiring. We can advise you from there.
http://www.doityourself.com/forum/el...-pictures.html
 
  #8  
Old 05-29-16, 06:57 AM
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A question here where the pump gets 120 power from?

Zone valve end switch closing activates a relay in something that powers 120VAC to pump.

Follow the pump AC power cable back to where it comes from and check that out.
 
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