First co air handler blowing cool air.

MrB

I have cool air coming out of the first floor vent. The second floor has a separate air handler and is blowing hot air.

I checked the air handler at the hot water coil area and felt theres scalding hot temp at the inlet but the return is cool to the touch all the way back to the oil boiler.

I tried to bleed air from the bleeder valve on the hot water coil. It did help a little and the return got slightly warm. I probably didnt do it long enough or not properly.

Theres one circulator pump for all 3 zones.

Money is tight now with whats going on and oil prices hit $4.20 in my area. Im trying to see if I could tackle this problem without calling an "expert".

Anyone have an idea what to look for next?

STEVEusaPA

If your pressure gauge is working your pressure is dangerously high as it should've blown the relief valve. If your valve isn't working you're risking a dangerous catastrophe.
The price of oil just jumped this week.
Better get a pro. This is not a place to skimp and save money.

mattmia2

Is that a 50 psi boiler with a 50 psi relief valve? No reason to run it that high but it might be rated for it. Can you show us a clear picture of the ratings plate on the boiler? Is the system currently hot or cold?

MrB

Thank you for replying. Here is the images. Also, we do get hot water and the second air handler is working as design.

mattmia2

So the problem is probably the zone valve. If you turn another zone on with that zone, does it heat? I'm thinking the end switch in the zone valve isn't turning the circulator on. What bout if you move the manual lever on the zone valve for that zone to open?

We do need to look at the pressure too. The boiler is rated for 50 psi but there is no reason it should be more than 20 or so with the system hot. What is the pressure when it is cold and when it is hot? that gauge could be bad too.

MrB

How do you test to see if the end switch is bad? When I pull the level to manual, i could see the small cog turning. I will check the guage when I get home later on, the boiler should be cold.

mattmia2

the easy way would be to set one of the other zones to call then turn that zone on at the same time. the end switch from that other zone should do the same thing as the broken zone's end switch, either just turn on the circulator or turn on the circulator and fire the boiler.

Is the circulator running when the air handler is blowing cold?

SuperTech

It sounds like the hydro coil is air bound. If that gauge is accurate than your boiler pressure is dangerously high and the only device that prevents catastrophic failure, the pressure relief valve, is not functioning. Most likely your expansion tank has failed causing the high pressure and your air vents are not working which led to the coil becoming air bound. 

I would confirm this by removing the tank and checking the pressure on the bladder. If it has failed I would install a new expansion tank and charge it to 15 PSI. Install new pressure relief and replace any automatic air vents. Purge the airbound zone and you should be good to go. 

I see you are in my area. If you decide to have a pro take care of this (probably a good idea) my company would be glad to help you out and probably won't be as expensive as the company on the sticker on your hydro air unit. PM me if you are interested. 

reggi

@MrB ^^^^ THIS ^^^^

MaxMercy

It's showing 40 lbs on a 50 lb boiler. With only two stories to your house, it still should be half that. Like others have said, verify the pressure first.