No heat :(

smkrepe

The problem- furnace only kicks on to heat up the water to temp within the furnace and then shuts off and never comes back on until it needs to reheat the water again. I never hear any circulation kick on and my pipes do not get hot. Down where the 2 circulation pumps are they seem very hot to the touch. I have 2 zones
Things I’ve tested- I’ve tested both boxes where the thermostats connect and I got the 24v on one but not the other but when I turn up both thermostats the switch does open or close. I also do get the 120v coming into all the different boxes.

Hello, I have a Vaillant oil fired boiler
Model F70-W-45 and over the summer I drained the system and 2 weeks ago I refilled it because it’s been cold and the wood stove wasn’t cutting it (I usually rely on just the wood stove). Well my furnace ran for a week and then shut off. I went to home Depot and the guy there sold me a control board but when I got home I realized there is nothing on my system anywhere close to what he sold me so I returned it. I decided to to just start switching things out from research I did online. I replaced the cad cell which the old one didn’t appear to be bad and what I mean by that it wasn’t dirty or gunked up but people say try that first so I did and it didn’t change anything. I then changed the oil burner control box which was a Honeywell r8184g This also made no difference so then I changed the aqua stat and put on a l8124c Honeywell which was the replacement for the L8024c that was on there. I don’t know what to do next or which way to turn. Any help or advice is greatly appreciated. Thank you

Alan (California Radiant) Forbes

You took the long way home.

It sounds as though you don't have any water in your system. Those hot pumps; they are water lubricated and will overheat if either they're not turning or there's no water to keep them cool. That's where I'd start.

Those Vaillant boilers are tough. Too bad they lost faith in the U.S. and left.

DZoro

Why did you drain the system?
Controls are probably not your issue. Your issue is air in the system. You need to purge all the air out of all the radiators and piping. Depending on system design this can be quite a task. Post some pictures of your system and radiators.
D

smkrepe

I probably shouldn’t have drain the system but I did it because I use the woodstove a lot and I didn’t want the water to freeze up on the second floor. I am thinking that one of my circulator pumps have sediment build up now. Last time I had a pump changed the guy said that my system auto purges the air. I have baseboard not radiator

smkrepe

I am going to drain the system again today so that I can take a look at the inside of the pumps and see if there’s build up causing the pump not to run. The pumps are taco

Zman

DZoro said:

Why did you drain the system?
Controls are probably not your issue. Your issue is air in the system. You need to purge all the air out of all the radiators and piping. Depending on system design this can be quite a task. Post some pictures of your system and radiators.
D

Yes

Intplm.

The circulators might be bad but probably not. It sounds like what @DZoro said. You need to get water in that system and purge it manually. Whoever said that the system auto purges is mistaken.
After you get the system full of water, (no air) up and running.
You should charge the system with nontoxic antifreeze so that you don't have to drain it again.
Especially the way you are heating your place. I have heated with wood . When I first started heating with wood years ago I put nontoxic antifreeze in my system to prevent what is happening to you. It works great, and you should never have to drain the system again.

Grallert

What is your gauge on the boiler reading? As said above it really sounds as if you have no water in the boiler or not enough water. The gauge should read about 12psi. If not? let the boiler cool off and add water. Take some pictures if you can.

smkrepe

So there’s no gauge for the psi on my unit. Only a gauge for the water temp. I removed both circulation pumps and they were slightly frozen until I spun them with my hand and rinsed them under warm water now they spin freely. One of them was full of water and felt a little sluggish so I’m assuming that one is probably bad because I don’t know if they were supposed to be full of water or not. And when I shook it upside down water was coming out if it and it was grey so I’m assuming it’s probably grease inside that cartridge. I also tested the motors on both pumps and both motors work fine. I have a second cartridge from a long time ago that I’m going to put into that 2nd unit instead of the one that was full of water. Are those cartridges supposed to take in water? It looks like a tight seal under the impeller and doesn’t look like it supposed to fill with water. I know that my unit had water in it but it wasn’t bled so I’m sure there was air in the lines but it did run fine for a week before stopping. Those impellers were slightly frozen before I spun them with my hand they almost immediately spun better after I manually spun them and rinsed them. I’m really convinced that the motors weren’t spinning the impellers and there was air in the lines, I’m going to get to this later today and fill it back up and bleed it and see where we are at after that. Do you guys thing this is a safe assumption? I really appreciate you guys giving your input, thank you

Intplm.

It could be. Seems you have a good idea of what to expect as you have DIY'd your system for some time now.
You may have some frozen spots on your rads and or piping that will interfere with with water flow and of course heating. Be on l
the look out for that during start up.

Can't say this enough, but you should put antifreeze in your system. It is better for the boiler, you and everything else that you have talked about.

smkrepe

I will add the antifreeze this time, I agree that s a great idea. I’m going to hook it all up now and I’ll let you know how I make out. I have baseboards no radiators but I’m sure something could also clog in those

smkrepe

Ok so after freeing up the impellers I purged the whole system and zone 1 works as it should but zone 2 the pipes stayed cold but I could hear the impeller moving and feel the flow. I went upstairs to zone 2 thermostat and switched it off and on a few times just for the hell of it and when I turned the thermostat down (no heat call) my pipes got hot on zone 2 which is the first time it got hot. What does this mean? Why would the hot water flow when the thermostat isn’t calling for heat?

Intplm.

Probably a slug of ice thawed through.
Check to make sure the thermostats are wired correctly, and check the circulator again for proper operation. Your circulators should not have to be taken apart and put back together as you are describing.
As to the flow of hot water, your flo-control valve might be out of adjustment or broken?

smkrepe

Thermostats seem to be working
Properly now. When calling for heat on zone 2 hot water only flows up the pipe which is about 6 feet high and then runs horizontal the rest of the way and the horizontal part is not hot. So what I’m saying is the hot water is not flowing through the zone 2 pipes.

HVACNUT

Post some pics so we can show you how to purge the zones.
Hope they're not frozen.

DZoro

Pictures of the system will help.
Air, ice are probably still the issue. Do you have bleeders at the radiators? Double check your temperature gauge, does it have 2 dials one for temperature and one for pressure? Pressure is important really do need to know the pressure.
D

Intplm.

Still need to purge more. Pictures as asked above.

smkrepe

So I bled the system again and it’s finally working, I feel like it was mostly air like you guys were saying. What did the trick is the last time I bled it was I opened the flow control valve, I didn’t do this the first couple of times. I was watching a YouTube video and saw it but I didn’t think I had one. Mine is hiding pretty much on the floor on the back of the furnace I didn’t see it. Here are some pictures of the system. The only thing now is when zone 2 kicks in I hear a loud rattling from that black valve on the pipe in the picture. Is it an air valve? There are quite a few of these within the lines

smkrepe

Here are photos of the setup

Alan (California Radiant) Forbes

Those are flow-checks which prevent gravity flow, also called phantom flow. Inside is a weight that sits on a valve seat. When the pump turns on, the flow will raise the weight, allowing flow. When the pump turns off, the weight drops down over the seat, stopping the flow so that the zone does not heat when the thermostat is off. You can raise and lower the weight with the thumbscrew.

You should be able to purge the lines with those two hose bibbs on the returns, but only if there's a shutoff valve downstream.

HVACNUT

What's the pressure on the boiler?
You dont need to open the flo valves to purge. Close them back to where they were.
In the 4th pic the purge station on one zone has a blue handled shut off valve and a red handled drain valve. To purge the zone did you close the blue valve and open the red drain valve? Purge until theres steady water. No air spurting out of the hose.
The feed valve on the bottom looks a little suspect to say the least. If its not feeding water to take the space left by the air being purged, its sure to cavitate and remain air bound.
I wanna watch someone replace that PRV without popping the top off.

Grallert

That gauge on your boiler would tell you both pressure and temperature if it were functioning properly. The bottom scale is pressure but it's unreadable. That is a very important scale to have, with out it you are only guessing whats going on inside. Replace that. Relocate the PRV and make sure it works or better yet replace it with a new one.