I've noticed two problems with my heating system, but not sure if they are related. Here's the background - sorry for being so long winded.

Background:
I have a Weil-Mclain Gold CGi Series 2 (which was probably installed in the 2002/2003 time frame). I have four zones:
Zone 1 - main floor
Zone 2 - upstairs (bedrooms)
Zone 3 - indirect water heater
Zone4 - radiant floor in the kitchen

I also use Honeywell programmable thermostats for zones 1 and 2, and a manual thermostat for zone 4.

At night, the temperature for zone 1 (downstairs) is programmed to drop from 66 to 62 and zone 2 is set for 66.

Problem 1:
On at least 3 or 4 occasions now in the last month, right before bed, I do a final check and have noticed zone 2 (upstairs) drop to as low as 63 (about 1 degree higher than downstairs), even though it is set for 66. My guess is that it is no longer switching on, but the downstairs heat is rising and keeping it at 63. Switching the thermostat from heat to off and then back to heat again seems to reset it and all seems to work fine for the rest of the night - with one exception...

Problem 2:
Again, not sure if this is related or not, but since my bedroom is above the furnace room, I can hear the furnace blower when it turns on, and several times now, I've heard it cycle on for about 10 or 15 seconds, then off, then on. It does this 3 or 4 times before finally cycling on and staying on for several minutes. The following morning, when zone 1 starts requesting heat, I don't notice this cycling problem anymore.

Any thoughts?

Sounds like you have control/thermostat problems. You will be better served by a on site visit from your local HVAC professional since these intermittent problems cannot be diagnosed here due to the fact that a much closer examination of the system is necessary than can be accomplished on this site. Sorry but it is all guess work with this kind of problem unless you are at the unit and perform proper control testing.

You seem to like to micro manage your system and that is good that you notice these problems but unless the fault is pronounced we do not know exactly what direction to send you in to come to a conclusion for your problems.

UPDATE:

HVAC guy came out today. Felt it was a sticky relay in the air handler and replaced it. Items leading to this decision were:

1. Boiler appeared to be working since other zones were not having any problems (though the occasional cycling of the boiler is still a mystery)

2. Hot water was getting to the air handler - so the pumps were working as well.

3. Air was not blowing from the handler when it should have been. Turning the stat to manual fan would begin blowing hot air, but when set to auto - sometimes would work, sometimes wouldn't

4. Turning stat off and back on would sometimes fix the problem - probably because it would reset the relay.

Regarding the boiler cycling issue - recommended a boiler cleaning and keeping an eye on it to see if the flame sensor is going bad.

Thanks for the update. It was in the control system/thermostat so my guess was correct. It was a smart move on your part to call for on site service and get fixed. It is cold out side. LOL

I do need to vent for a moment. As I researched this problem further, I've come to realize that the fan relay is a fairly cheap device and probably fairly easy to install. However, to fix this problem, I was charged $65 for the service call, and another $250 for the part. Is it just me, or does this sound completely unreasonable?

I do understand your feelings in this situation but it is expensive to be in the HVAC biz today. As to mark up or costs of business, keep in mind a quality contractor that will be there for you when you need him may have some or all of the following business expenses:

Not limited to;

401K
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