Hoval Variolyt

Post by **Bonz** » Sat. Jan. 20, 2024 8:41 pm

New to the caol world. I'm having a problem getting heat out of the boiler. This is a "New" install with a circa 1986 Hoval. I'm using it to back feed my Buderus G115/4. Basically I'm using it as a heat source. The problem I'm having is I'm not getting the water temp to where I want it. I'm trying to run it between 170-180 degrees but only getting to about 135. I was originally thinking I didn't have enough water mass and was drawing all the BTU out but I don't think that's the case any more. The mfg. Label indicates the stove/boiler will produce 110000 BTU on coal, which is more the the Buderus. I should have no problem in theory producing the heat I need. I just can get the water temp up. As I write this the fire box has about an 8" bed of coal. Shoot temps inside the box the wall temp was about 360-370. Coal around 970. What am I missing. Manual damper on the base, no blower on the unit. No barometric damper.

Post by **Bonz** » Sat. Jan. 20, 2024 8:42 pm

How do I upload pictures?

Post by **Bonz** » Sat. Jan. 20, 2024 8:56 pm

IMG_20240101_120114386.jpg

Post by **StokerDon** » Sun. Jan. 21, 2024 8:28 am

Welcome to the forum.

What are you trying to heat? Sq Ft, heat loss? Looking at your picture there are a few things I noticed.

Where is the boiler? There is a window and 2 uninsulated walls showing. If the boiler is in an uninsulated area, a lot of it's heat will be used to heat the area.

What size are the supply and return pipes? They look small, maybe 3/4"? You will have a tough time getting 110,000 BTU through a 3/4" pipe.

I can't see all of the stove pipe but I don't see a barometric damper. If one is not installed and set up properly a lot of heat could be going out the chimney.

-Don

Post by **waytomany?s** » Sun. Jan. 21, 2024 9:32 am

He stated no baro. How does one pipe circulate water?

Post by **Bonz** » Sun. Jan. 21, 2024 11:50 am

Thanks for taking a look. So this is the what have. The stove is located in the garage but really just to keep me and it out of the weather, not heating any of the space. The boiler is back feeding the main boiler in the house so I didn't have to move all the controls. The system is piped all in 1" copper. Total head the the circ has to deal with it 13' which is done by a Grundfos 3speed pump. The problem that I'm have is the boiler is run cold, not making any heat. Been on the 2 days burning coal and have not the the water temp north of 150 and the with the circ in the off/ standby position. The on the flue pipe is 110 degrees. Thought it might have been a draft issue with the chimney I built. Got up on the roof this morning inside the chimney clean as a whistle. Took a 5 foot section of 10 duct work and extended it 5'. This is just a temporary section on top of block and tile chimney. Maybe helped a little but not what I'm looking for. Boiler just doesn't want to make heat.

Post by **Bonz** » Sun. Jan. 21, 2024 11:56 am

IMG_20240121_115218417_HDR.jpg

that's what the fire looks like.

Post by **StokerDon** » Sun. Jan. 21, 2024 4:36 pm

Bonz wrote: ↑Sun. Jan. 21, 2024 11:50 am The stove is located in the garage but really just to keep me and it out of the weather, not heating any of the space.

Yes it is. You are loosing heat from the boiler and the piping into the uninsulated, unheated space. I think you my not realize how significant this is for a small boiler.

Also, with no barometric damper, you are loosing heat up the chimney.

Is the garage attached to the house?

Again, it would be helpful to know what kind of house you are trying to heat. Sq ft, good windows, insulation? And what part of the world it is in?

-Don

Post by **Bonz** » Sun. Jan. 21, 2024 5:15 pm

Any help is good help thanks Don. The the is 1600 sq ft with in insulation through out Basically I have gutted it and re- done everything. Since that picture was taken the pipes have been wrapped in insulation. I don't the the heat is going up the stack because the stack has no heat. It's between 100-110 two inches out of the back of the boiler. You and use it has a hand warmer without getting burned. Not sure if the size of coal makes a difference but I was running stove size up until about 30 minutes ago. The reason being the hate in the bottom has large slots and Nut can fall through it when is down to 1/2-3/4". Just put about 20 pounds of nut onto the bed. All windows have been replaced along with New Doors. With the water temperature around 150 the house is comfortable. Existing heat systems is a combination of radiant and hydro air. The problem is maintaining the water temperature. Would like it around 170. I'm not even close. Also I have an 80 gallon buffer tank in the system for additional water mass so that have additional BTU to drawer off of. Basically I want to operate it like an outside boiler l, it's just located in my garage.

Post by **Bonz** » Sun. Jan. 21, 2024 5:20 pm

Just to clarify. The garage is attached to the house and the existing house boiler backs up to it on the other side of the Wall. The total length of pipe in the garage space is 20 feet, 10 on the supply side and 10 on the return side.

Post by **Bonz** » Sun. Jan. 21, 2024 5:33 pm

Don, one other thing you mentioned was heat loss the boiler because of the location. I understand the garage is cold but the boiler is insulated. Specifications indicate it can be with in 6 inches of the Wall. So I get that I might lose the temperature but no way 30 to 40 degrees. By the way the house is s a ranch with an open floor. The only rooms with walls are the bathroom and bedrooms.

Post by **ShawnLiNy** » Thu. Jan. 25, 2024 3:00 pm

Are you filling firebox to tops of bricks ?

Post by **Bonz** » Sun. Jan. 28, 2024 1:33 pm

Filling it to the manufacturer recommended height. I have been able to get much better heat out of it but getting the circ pump to cycle. Original the pump was on 24/7. I'm thinking that was keeping the temperature for rising. Now the I have it turning on at 165, and off after a 150 it's much better. This boiler is designed to back feed the existing system/boiler. I'm trying to get more consistency out of it.

Post by **BunkerdCaddis** » Mon. Feb. 12, 2024 6:39 am

If in the picture of the boiler the temp is at 130 degrees, it appears the chain on the draft control looks loose. If you want a higher temp the draft door should still be open, doesn't look like it is.

Post by **Bonz** » Wed. Feb. 14, 2024 1:51 pm

The way that I'm running the damper now is at a fixed position. It seems to give me better performance, even though it's using a little more fuel. Thanks for the advice. Always looking for a better way. Once I get the rest of it ironed out I will go back and set the damper up right.