Can an ESBE VTC511 valve go bad, and how would I know...

Zach Hoyt

Member
Feb 11, 2015
16
Orwell NY
I am confused about what is going on with our boiler and I am hoping someone will be so kind as to point me in the right direction. We have had a Wood Gun 140 since 2012, and in previous years when the weather got cold sometimes the boiler temp would get low, and I would have to figure out what about it wasn't happy so that it would burn hotter again. This year we have had times when it was cold in the building and I have been trying to get it to warm up, but the boiler has stayed hot all the time, and I am wondering if the water isn't circulating properly.

I replaced the Taco 007 circulator pump which runs the whole system a week or so ago, but it didn't help. I figured that pump was 8 years old and it wouldn't hurt to replace it anyway. The only other thing I can think of that might be restricting the flow is the ESBE VTC 511 valve in the return line. It is also 8 years old, and I have not been able to find any reference to how long they should be expected to work, or how to test one when it's installed. I'll be very grateful for any advice. Thank you very much.
 

Don Hayter

Member
Feb 14, 2015
4
Penticton BC Canada
I am confused about what is going on with our boiler and I am hoping someone will be so kind as to point me in the right direction. We have had a Wood Gun 140 since 2012, and in previous years when the weather got cold sometimes the boiler temp would get low, and I would have to figure out what about it wasn't happy so that it would burn hotter again. This year we have had times when it was cold in the building and I have been trying to get it to warm up, but the boiler has stayed hot all the time, and I am wondering if the water isn't circulating properly.

I replaced the Taco 007 circulator pump which runs the whole system a week or so ago, but it didn't help. I figured that pump was 8 years old and it wouldn't hurt to replace it anyway. The only other thing I can think of that might be restricting the flow is the ESBE VTC 511 valve in the return line. It is also 8 years old, and I have not been able to find any reference to how long they should be expected to work, or how to test one when it's installed. I'll be very grateful for any advice. Thank you very much.
I have the same valve. When I first fired up my system I got debris (copper pipe filings) stuck in the valve which caused my boiler to overheat. I removed and cleaned the valve and flushed the system which fixed the problem.
 

Don Hayter

Member
Feb 14, 2015
4
Penticton BC Canada
I have the same valve. When I first fired up my system I got debris (copper pipe filings) stuck in the valve which caused my boiler to overheat. I removed and cleaned the valve and flushed the system which fixed the problem.
You should be able to remove the thermostat from the valve without removing the valve. Put the thermostat in a measuring cup and add boiling water. The thermostat will expand and contract with the temperature change. The movement is only about 1/4" if I can remember correctly.
 

Zach Hoyt

Member
Feb 11, 2015
16
Orwell NY
Thank you for your help. That's interesting about the filings making it stick. The boiler and this valve are 8 years old, but the rest of the system goes back to the mid 1990s, and was installed before I was here. I ordered a new thermostat yesterday and am planning to swap it in when it comes next week. After 8 years the old one might have gotten gummed up, or something, and the new one isn't too expensive. I'll test the old one when I take it out, I figured it would be the same as testing an automotive thermostat. The old valve body looks like new on the outside, so I hope the inside will still be in good condition too. I tried to order the replacment O ring that is mentioned in the installation instructions for the valve but Supply House didn't have it, so I hope that if I end up needing an O ring I can get it in town at the hardware store.
 

Jeff S

Feeling the Heat
Aug 31, 2008
344
Kimball,Michigan
A stuck thermostat could prevent or limit the hot water going to your heat emitters. Do you Have a way to check temperatures of your pipes ? If nothing else you can do it my touch. If I remember correctly replace thermostats for your unit are inexpensive ,wouldn't hurt to have a spare.
 

Jeff S

Feeling the Heat
Aug 31, 2008
344
Kimball,Michigan
I will be the first to admit I know nothing about a wood gun, is this a gassifier ? I had a situation with my unit this week where it just wasn't keeping up and the temperature in my storage tanks was dropping like a rock. Well I went back and read the sticky on fine tuning your EKO boiler and how to adjust your primary and secondary air. Of course I done all this years ago so why would that be a problem, well as it turned out my primary was filled with 13 years of gunk and was plugged up. After a cleaning this out and readjusting by boiler is cranking out the heat. Like anything this didn't happen all at once but gradually and I've noticed that my efficiency has decreased a little each year. It pays to give everything a look over and get back to basics.
 

Fred61

Minister of Fire
Nov 26, 2008
2,444
Southeastern Vt.
You say the boiler is hot! How hot? Is the temperature above the launch temperature of the circulator? If so, what temperature do you have the aquastat set for? Hopefully it is set higher than the value of your boiler protection valve which is normally 140 ::F.

This scene plays out when firing up a cold boiler. Firebox is loaded and lit -- cold fire slowly warms the water surrounding the fire -- You may see condensation on the walls of the firebox early on, this is especially true with a Wood Gun -- when the water in the jacket reaches the launch temperature of the circulator it will circulate through the bypass bathing the bulb of the thermostat -- when the water circulating through the bypass reaches 140::F the thermostat starts opening allowing system water to start flowing -- at this point I suspect there is some fluctuating of the thermostat as cold water from the loop mixes with the bypass water -- when the loop water reaches 140::F, the thermostat will stay open, allowing the system water to continue flowing.

There could be a scenario where there could be something restricting the flow in the system causing the circulating water to take the route of least resistance and flow through the bypass instead but I doubt that is happening. In fact I'm wondering if the boiler protection is really the cause of the problem at hand. We may know better after you answer the two questions posed above.
 

Jeff S

Feeling the Heat
Aug 31, 2008
344
Kimball,Michigan
Fred is spot on with temps. The thermostat in the mixing valve is not an "all on"or "all off" scenario but can vary (throttles) how much it opens until it gets past its intended setting and if your trying to draw heat from your boiler while its hoovering around that set point your just not going to be a happy camper. Not sure if you have any storage other than what's in the boiler but a storage or "buffer tank" helps tremendously when you go from a mild day to one that's more frigid.
 

Zach Hoyt

Member
Feb 11, 2015
16
Orwell NY
The new thermostat arrived last night and I put it in today. Everything seems to be back to normal. When I tested the old thermostat it didn't move in a pan of water on the stove, and there was some gunk built up on the shaft. The boiler is continuously hot year round, and the circulator is always running. With the old thermostat the boiler was staying around 170 most of the time, and if we turned on more than 3 of the 7 heat zones at a time, or when it got colder outside, the boiler would stay hot but the temperature inside the building would fall. Normally when it's cold or there is a lot of demand the boiler temperature drops to around 150 and I have to tend it more often to make sure it's burning optimally, then when things get easier it will climb back up again. I think the thermostat must have been stuck half or so open, because there was some water flowing, but not as much as usual, and the hot line from the boiler was vastly hotter than the return line (by feel, I don't have an infrared thermometer). Now with the new thermostat the hot line from the boiler is not as hot and the return line is much hotter than it was. Thank you all very much for your help and advice. I'll get another thermostat to have as a spare when I order a new spare circulator.
 

Jeff S

Feeling the Heat
Aug 31, 2008
344
Kimball,Michigan
Glad you were able to get everything back to normal.
 

Jeff S

Feeling the Heat
Aug 31, 2008
344
Kimball,Michigan
Not trying to talk you out of a circulator but it doesn't sound like there was anything wrong with the one that was removed other than being 8 years old.