High and low fire problem of Webster JB1C-07

ben_18

A Webster JB1C-07 was installed on 50 HP steel tube Eastmond boiler. It is a gas-oil burner and is running on gas. It was set with a low-high-low firing pattern as per a previous discussion on this forum. The problem is clocking it at the gas meter shows:
LOW 1.2 million btu/hour
HIGH 1 million btu/hour
This doesn't make sense!
And this is after a technician came to adjust it. The low used to be at 1.6 million. For some reason he was able to adjust the high to as low as 700,000 btu but he couldn't get the low fire any lower.
Has anyone encountered a similar problem?
(The communication among this big service department is bad and it has been hard to get this tech to speak to the guy in charge and admit to him there is a problem.)

aircooled81

Does the gas butterfly valve open atleast 75% at high fire?
Did he adjust the gas by stack-gas analysis?

aircooled81

Did anyone adjust the reg? Basically, do you have addequate gas pressure at high fire?

ben_18

I'm not sure about the rest but he did have about 2.5" wc at high and maybe around 1.5" at low if I remember correctly. He did a combustion analysis. And if he would go below 1 million on the low the numbers weren't good on the analyzer.

aircooled81

If you can, was 2.5"wc manifold or inlet gas pressure?
Nameplate will tell you what inlet should be, manifold is likely there too. What do those state?

EBEBRATT-Ed

I am assuming this is low-high fire that it has a two position gas valve (not full modulation with a butterfly valve). You must take furnace (pressure + or draft-) and figure that in with the gas pressure calculation. You do this by using a manometer or a magnahelic with both a high and low pressure taps. High goes on the burner head and low goes to the firebox. I am assuming the gas readings given were taken at the burner head. Don't forget that the required gas pressure readings are given with 0 furnace pressure

nicholas bonham-carter

It's just too bad, and all too common that the so-called tech was ill prepared with knowledge, and training to set this up for you. This burner adjustment is just before the final stage of making your system well balanced. The final stage is getting the main venting in order, so you are not getting the Webster to burn a lot of extra gas, in order to push the air out of the radiator vents, instead of the main vents.--NBC

aircooled81

Regarding your original post, i am very impressed you clocked the gas meter. I beleive they (the shop who provided you this service) needs to correct this for you. If they have large communication errors, and are not interested in your satisfaction, well then you need to find a new shop.
I think the original techs opinion is probably mute at this point, if they are hesitant to return sooner than later, after you have explained to them this factual observation you have made, thats just not right.

ben_18

@aircooled81 It was a big job and I wanted to make sure they got it right. When I first clocked the meter and saw the HIGH was lower than the low I thought I was making a mistake. But the tech came and confirmed this.
I can't find another company because they are the ones who installed the burner.
I think the pressure was measured after the regulator at the burner head. The tech thought it might be the gas valve and checked the pressure and said it was good.
@EBEBRATT-Ed It has only two positions high and low

Is it possible that they HIGH is lower than the LOW?

JUGHNE

If it is a hi-low gas valve could the 2 wire connections be reversed? FWIW

ben_18

They could. And then it will start on high and go to low. but then if i switch it over to oil it will run the wrong way. The oil part is working fine

JUGHNE

I refer to the terminals on the 2 stage gas valve.