I have a shaver 290 and for the most part it is great, but like some of you I have had a couple issues. My biggest concern is the water steaming off, I am down several gallons a day and steam constantly at all temps. My friend, who has the same furnace uses no water in a 2-3 week time frame and has basically the same installation with the same parts. I think I have discovered the difference in our boilers and why some Shavers steam more than others. I've attached an image depicting our installations. My boiler (Boiler B) has a slight lean to the rear, where my friends (Boiler A) has a slight lean to the front, and possibly an upward angle of the vent tube exiting the boiler.
I believe the lean frontward lean and upward angle of the vent pipe on my friends boiler dramatically cuts down on the surface area of water exposed to the atmosphere. Boiler A's vent pipe is full of water, where Boiler B's is simply a passage way for the atmosphere to make contact with the entire surface of the water in the tank allowing much more steam to be created and exit even when the water is below boiling.
I slid a 1" piece of pex over my overflow and and secured it with a hose clamp. Then added a short 90* and another 1-2" of pex vertically. The boiler water level is now raised slightly, but would still be vented and the surface area of the water exposed to the atmosphere would only be the area inside the vent pipe instead of the entire top of the tank. Another side benefit is I can see my water level in the pex, as I have a pink rust inhibitor additive that shows through the pex. If you run straight water clear flexible pipe attached to the vent, bent upwards and held in place with clamps on the side of the boiler should be an easy fix, just don't extend the pipe up too far or you may risk overflowing out the water coil cover.
Here is a quick sketch of the two scenarios (boiler A and boiler B) as well as a diagram of my proposed fix (bottom right). I've been running this for a day now and have seen zero steam and have lost zero water. I don't think the water in the pex will ever freeze as mine is quite hot (160*+). Does anyone see any problems with this? I sent an email to shaver for their input and am awaiting a response.
Here is my steam fix, I keep the water at about halfway up the pipe so I can track any level changes. My vent use to steam nonstop, but no more.
I replaced the original thermostat because I had bad luck with it and boiled the water a couple times. I also wanted a thermometer to tell me the water temp inside the boiler (I have one on the line coming off the OWB but it is only accurate when the pump running). It's funny you mention inside application, because the controller I have sends a signal 0-10v for a remote monitor, still deciding if I want a display inside to tell me the temp of the boiler. My Ranco is working fine, I'm going to move the well to a better spot . Another guy gave me a great idea for a thermostat well. He used a 12" piece of 1/4" copper, capped one end then flared the other. He then drilled a hole on the top of his water jacket near the cover in the back. He dropped the copper pipe down the hole and the flared end kept it from falling in all the way. dropped in his sensor and siliconed the top. Said it's dead nuts accurate. I plan on doing this to mine this weekend. Here is a pic of it, it is mounted inside the rear door:
I still need to do some cleaning up and insulating on the rear of the boiler, but I have a few more adjustments to make first.
My next project is to modify my blower damper to operate like the natures comfort and Hardy OWB. They use a solenoid to cover and uncover the blower inlet when the fan is on/off. Here is a pic I borrowed from fellow member (derwood91, thanks for the pic):
I modified my spare blower yesterday. I re drilled the flange so it can be mounted with the door facing up. Then I drilled out the door rivet and cut out the grill off the air inlet. I the door to a hinge so it will swing up and put an eyelet in the center of the door. I'm going to mount it on the boiler this weekend and attach the door to a solenoid that will activate and lift the door when the blower turns on. When the blower turns off, the door will close and limit draft. I think this will help the boiler recover quicker when the blower is on, more air entering because the door will be wide open. When the blower is off, the fire will smolder better and not overheat the water. I'll take pics this weekend and let you know how it works.