Boiler not building pressure

steamnovice39

So to start things off I have a peerless wbv-04 steam boiler that I just converted to gas with a carlin ez gas burner. The btu firing rate is 150,000 btu which matches the old oil burner which I confirmed. I'm estimating the boiler to be 19 to 20 years old with a municipal water supply with heavy chlorine.
The system has been redone by me a couple of years ago with double antlered Gorton (biggest main vent) vents, all new Gorton rad vents, all rads pitched, new 2" riser to 3" drop header, with 2 main take offs. The boiler was also very dirty which took a long time for me to get clean, and then maintained water with steam master tablets.
When I fired the boiler for the first time this year towards the end of the heating cycle it started to build pressure, which it always did before. I have the vaportrol set at 8ounces cut out, which the boiler always hit easily. Once I hit about 5 ounces of pressure the boiler lost all pressure, and I couldn't build any no matter how long the boiler ran. When I look outside at the top of the chimney I see what looks like steam coming out. However I'm not sure if it's just water vapor from the natural gas condensing since it's been very cold. I live in CT.
I filled the boiler up with water but didn't see any water coming out of the boiler jacket, but I never checked the inside of the boiler along the flue passage way. I'm also losing a negligible amount of water when it runs. Can I try and locate the leak and hit it with boiler epoxy to get me through to the spring?
My boiler of choice is the Burnham megasteam with the Carlin ez burner I have now. I will have to do it myself since I don't have the money to pay someone, but I'm more than comfortable doing a double riser to my 3" drop header, and hooking up the controls and returns. It will just take me a couple of days. My question is, what is my best option?

Jamie Hall

If she won't build pressure, but used to... sounds like a leak -- and most likely from the water side into the firebox/flue side. It should, however, be evident in increased water use (although, perhaps, not that much).

I doubt very much that you can persuade the leak -- if there is one -- to stop with epoxy. Particularly if it's between the water and the fire side. No harm to trying, of course -- but I wouldn't hold my breath.

Fred

So, have you clocked the gas meter to determine you are running at 150K BTU? It is possible you are not, especially if you did the conversion yourself and if you did not have the equipment to properly set the burner up. Also, if it built 5 ounce of pressure, then lost it, during a single cycle, I'd be surprised if you just happened to be standing by on the one cycle where the boiler sprung a leak and lost pressure. I'm guessing you either aren't getting the gas supply you should from the gas supplier or your new burner isn't properly adjusted. Have the gas company test their meter and pressure.

clammy

Pull the flue collector off and look at the top of the boiler you surely will be able to see something ,you could also pull the burner mounting door off and check from the fireside aside from flooding the boiler and looking for leakage . I think you should take a look about your whole system check radiator valves,vents and all your piping for any evidence of leaks it doesn’t take much and it adds up.peace and good luck clammy

Hap_Hazzard

You can use a borescope to inspect the flueway for signs of leaking. If you don't have a borescope, here's one I found on Amazon: https://amazon.com/gp/product/B01MYTHWK4.

steamnovice39

I clocked the gas meter per the manual and ran the equation. I'm running at 150k btu. My lines are sized correctly and I'm getting 6 in of water column at the burner. Eversource already came out and checked everything. New gas line, new meter, and all new piping.
I don't have any radiator vents or valves leaking, and they are all only a couple of years old.
I had also pulled the pigtail off, the vaporstat, and the gauges to check for any plugs or issues. Everything was clear and working as intended. I tested the gauges off the boiler.

nicholas bonham-carter

Use the overfill test to see if the boiler is leaking, by filling it up to the header, when only warm, and not steam hot.
Let the boiler rest for an hour or two, while checking for signs of dripping in the burner area.
If there are no signs of water there, then any buried wet returns may be culprits. Those could be replaced by new piping above the floor.--NBC

steamnovice39

All my wet returns are above the floor and visible. I checked those and found nothing. I will flood the boiler up to the header and check the flue passage ways for any leaks. I think that's my only option at this point

Fred

I'm not sure what the implications are when converting from oil to Natural gas but I would think the nozzle used in an oil burner may well have been larger than what was originally installed in the old oil burner (even though it was rated at 150K BTU it may have been running hotter) and the gas burner may be sized appropriately at 150K BTU. Do you still have the old oil burner and can you tell what size the nozzle is and what the rating is?
1 gallon of diesel fuel or heating oil (with sulfur content less than 15 parts per million) = 137,381 Btu ; 1 gallon of heating oil (with sulfur content at 15 to 500 parts per million) = 138,500 Btu; 1 barrel of residual fuel oil = 6,287,000 Btu; 1 cubic foot of natural gas = 1,036 Btu; 1 gallon of propane = 91,333 Btu; 1 short ton (2,000 pounds) of coal (consumed by the electric power sector) = 18,911,000 Btu; 1 kilowatthour of electricity = 3,412 Btu

Also, do you have a 0-3 PSI gauge on the boiler or are you relying on the 0-30 PSI gauge? They are far from accurate. You say you are losing a negligible amount of water. Can you quantify what that means? How much over how long?

You do realize that Burnham will void any warranty on the Megasteam if a natural gas burner is used on it, right? While several of the Pro's on here see no reason why Burnham won't approve a natural gas burner on that boiler, be sure you understand the ramifications of doing so.

steamnovice39

So the old oil burner was a carlin burner with a 1.25 gph nozzle. I have the original boiler tag from peerless which states that nozzle being rated at 149000 btu input.
I have a 5 psi gauge on the boiler now that I confirmed is working. As for water loss I have lost little enough that I have not added anymore water to the boiler. However I am also manually turning on and off the tstat to control the run time of the boiler, and have only gone through 5 full heating cycles. I have also noticed that my heating cycles have become much longer. Where as it used to take about 30 minutes to heat from a long setback, it is now taking about 45 minutes.
I understand putting a gas power burner on the megasteam will void the warranty on it, but I'm locked into a power burner boiler now. I'm also under contract for using natural gas for heating now. It's a chance, but hopefully a calculated risk.

acwagner

What's your radiator EDR compared to the boiler output?

Alin

Overfill test can be helpful in this case

Fred

@steamnovice39 , you are creating too many variables for us to be of much help to you. Now you are saying you manually turn the Thermostat on and off. That means no heating cycle is a "Normal" heating cycle. There is no way you can consistently manage the room temps to the fraction of a degree that tstats are adjusted to and I'll bet the temp drops with a variable of a degree or more between cycles.
Do the Fill test, set the tstat to run like it is suppose to, and let the burner run like it was designed to and then let's see where you are. If there is no leak when you do the fill test and the house heats to set point (and once the room temp and all the contents are at temp), you are good to go. If it leaks, you have your answer.

steamnovice39

Yes I understand, and thank you to everyone for the advice. I have a Robert shaw tstat with a 1.5 degree differential, so it has always operated with a set back. Even with the set back it has heated fine, and built pressure. I'm manually cycling the tstat because it runs until the temp is satisfied which is a massive waste of fuel.
I will do the flue test and check the flue passage way and see if I can find any leaks and then go from there. As for the edr calculation I haven't done one yet because I'm still locked into my old boiler, and didn't want to downfire it. I plan on doing one before I size my next boiler.

acwagner

I would do the EDR calculation now. If the calculation shows that your boiler is right-sized, then you may not have a problem.

I have no experience with or knowledge of oil burners, but my guess is that the old burner was firing at a higher rate than advertised for some reason. Chances are it's a difference between the burn rates vs a leak. Although coincidences happen, it seems unlikely that right when you change out the burner a massive leak developed.

Also, keep in mind that developing pressure beyond what is needed to get steam to all the radiators isn't necessary or desirable.

steamnovice39

Yes I understand that very little pressure is the best for efficiency, and that's what I have tried to achieve.
I'm not sure how it could fire any higher since I thought I was locked in at the nozzle size and pump pressure. I tried to get exact information directly from peerless instead of relying on the boiler tag, but it's an 2001 boiler and they told me they don't have information on boilers before they were bought out in 03 or 04 I believe. So I was out of luck.
I do need to do an exact EDR calculation, I just haven't had the time as of yet. I believe the boiler at 150k btu is rated for 467 EDR.

steamnovice39

Well in case anyone was interested, I filled the boiler up to the header today, and let it sit for about an hour. I can not see any leaks or dripping of any kind. I still know my gauges are working, so I must have a leaker in one of my risers up to a radiator. All my wet returns, shut off valves, and air valves aren't leaking. I'm going to try and start trying to isolate piping to see where a leak might be.
I thought that the boiler might be downfired and that's why, but going off the boiler tag I'm set at the right but. I know my oil burner was a 1.25gph at 150psi pump pressure. How can I convert the BTUs from the oil pump, to double check my correct btu firing rate?

Chris_L

Why do you think you have a leak? Merely because your pressure gauges don't show pressure building?

If you home is heating properly, I suggest doing nothing--other than watching the gauge glass for a week. Assuming you don't have an automatic water feeder, mark the water level on the glass after the boiler has been off for a few hours. Do the same a week from now and tell us how much the water level has gone down.

If you do have a automatic feeder, hopefully you have a water meter on it and can tell from that how much water you are using.

acwagner

I agree with @Chris_L . Even with a 5psi gauge, it's hard to tell what pressure is going on if you're only at 5-8 ounces at the end of a cycle. Before the vents close, you're probably at less than an ounce. If your radiator load roughly matches your new gas boiler output, then you're probably living the dream and not building any pressure.

Let it run some and see if you have have a higher water loss than normal.

Fred

If it ain't broke, don't fix it!

steamnovice39

I don't have a water feeder and watched the water level all week. Level on the sight glass dropped about an 1/8th of an inch. I'm assuming that's a small amount of water.
I isolated each main by turning off all the shut off valves for the radiators. When I alternated each main I didn't notice any leaks, or blowing steam anywhere. I also built pressure quickly and cut out on the vaporstat. I'm guessing that the boiler tag wasnt the correct reference and with the gas conversion I'm just downfired.

acwagner

You don't need to guess. Calculate the EDR. Or post photos with some dimensions of your radiators and we'll help.

mikeg2015

If the output is slightly lower, then your main vents are proportionally larger and the steam often heats the radiators more evenly which actually consumed more steam and results in lower pressure. I’ve witnessed this on my system. As I slowed down the radiator vents, the pressure actually dropped.

I replaced the boiler recently with a used on (long story) and it’s both smaller and undersized than what it replaced. I build 0 pressure.... even on a 20 oz gauge. Needle never bounces, but I know the gauge works as overfilling the boiler above the gauge raises the needle.

System heats mostly evenly with some random variation in 2 or 3 radiators.

Be happy it’s running a low pressure. Less leaks, more even heating, and slightly better efficiency.

As a side benefit, the longer run cycles form lower firing rate result is less overshoot and overall more even temperatures. Everything just happens more slowly.

steamnovice39

I will try and do an edr tomorrow. I'm not worried about the burner being downfired besides the fact I know it can lower stack temp and cause condensing issues in some situations.