# Lochinvar copperfin issues



## Protech

So I have a commercial restaurant that needs 180° water coming out of a booster heater unfortunately the booster heater is under size so the only way I can get that temperature is if the main boiler is putting out 150 to 160° water. 


See the attached diagram.

The issue is that i can't get more than about 150 degrees out of the tank outlet without turning the boiler up so high that the T/P trips on the boiler heat exchanger. I have the boiler reset temp setting at 215F and the set point at 180f . The boiler cranks out 200 degree water but it never gets the tank up above 150F. I believe this is due to the cold water inlet being piped into the boiler return line to the tank. So the boiler is producing 200 degree water but it is being mixed with the 70-75 degree incoming cold water before it returns to the tank. My concern is if I move the cold water inlet over to the boiler supply pipe and away from the return pipe under certain conditions the boiler could be hit with a spike of 70° water and I'm concerned about cracking the cast iron headers on the heat exchanger.

Any input?


----------



## Protech

see diagram.

Tank never makes it to 150F before boiler reaches set point and shut's off. Then boiler kicks right back on and cycle repeats.


----------



## shlomy81

Sounds like ur pump isn't working fast enough or u don't have enough storage


----------



## rjbphd

I piped my like the 1st one.. no plm with temps.. I think you're not getting a proper flow thru the exchanger, partily plugged? Pump bad?.. what the delta T between the inlet and out at boiler?


----------



## Protech

rjbphd said:


> I piped my like the 1st one.. no plm with temps.. I think you're not getting a proper flow thru the exchanger, partily plugged? Pump bad?.. what the delta T between the inlet and out at boiler?


brand new pump and boiler. 500k btu boiler and 120gallon tank.


----------



## Protech

From the boiler manual:

"A lower boiler flow may cause noise on operation or short cycling of the burners."

but then later it says:

Boiler Flow Rates
Installation & Service Manual
￼￼￼￼
􏰀 CAUTION
The maximum flow rate through the boil- er with a copper heat exchanger must not exceed 30 GPM.
The heat exchanger is generally capable of operating within the flow rates of a residential heating system. Should the flow rate exceed the maximum allowable flow rate through the boiler 30 GPM) an external bypass must be installed. The bypass should be fully sized with a balancing valve to allow for proper adjustment of flow. Flow rate can be determined by measuring the temperature rise through the boiler.
The basic guide for minimum flow in this boiler is based on a 40°F temperature rise in most installations.


----------



## shlomy81

What's the demand u need what the pump gpm u have


----------



## Protech

So I throttled the circulation pump down so that on max fire the boiler has a delta T of just under 40 degrees.

The trouble is, now it won't heat the tank to the desired 150 degress and is short cycling.

WTF???

So if I open the throttling valve up I'm cavitating the heat exchanger and if I throttle it down the boiler short cycles and won't heat the tank.

I'm screwed either way.


----------



## rjbphd

Protech said:


> brand new pump and boiler. 500k btu boiler and 120gallon tank.


Do it come with the crappy 3 piece pump?? Make sure the impeller is turning.. and what's the delta t again?


----------



## Protech

shlomy81 said:


> What's the demand u need what the pump gpm u have


The draw from the tank is anywhere from 9.4 gpm up to 20 depending on what is running in the kitchen. There is a dishwasher that pulls 9.4 gpm continuously plus what ever intermittent hot water demands occur for three compartment sinks and handwashing and other domestic hot water uses. 

Circulation pump on the boiler if un-throttled is probably pushing 100 gallons a minute. I have it throttled down to the specified flowrate via Delta T called for in the boiler manual.


----------



## Protech

rjbphd said:


> Do it come with the crappy 3 piece pump?? Make sure the impeller is turning.. and *what's the delta t again*?


35-38 degress


----------



## Protech

picture of the boiler


----------



## slumplumber

Is there an aquastat located on the storage tank that controls the boiler and if so where is it located in the tank (top, middle or bottom)? Does the boiler pump run continuos or only when the burners are firing and if only when the burners are firing is there an off delay so the pump runs for a short time after the burners shut off? Does the T&P valve dump while in operation or on shutdown? Have you checked the firing rate of the boiler by either clocking the gas meter or by a connecting a manometer to the burner manifold? Is the system properly sized for the load? Are there any additional unused tappings on the storage tank and if so what size?


----------



## Protech

slumplumber said:


> Is there an aquastat located on the storage tank that controls the boiler and if so where is it located in the tank (top, middle or bottom)? *Bottom*Does the boiler pump run continuos or only when the burners are firing and if only when the burners are firing is there an off delay so the pump runs for a short time after the burners shut off? *Continuously* Does the T&P valve dump while in operation or on shutdown? *Operation* Have you checked the firing rate of the boiler by either clocking the gas meter or by a connecting a manometer to the burner manifold? *No* Is the system properly sized for the load? *I have no idea but this same boiler was installed for years and they have always had hot water though they have had the boiler replaced every 5 years.* Are there any additional unused tappings on the storage tank and if so what size *I'm not sure.*


see bold responses above


----------



## rjbphd

slumplumber said:


> Is there an aquastat located on the storage tank that controls the boiler and if so where is it located in the tank (top, middle or bottom)? Does the boiler pump run continuos or only when the burners are firing and if only when the burners are firing is there an off delay so the pump runs for a short time after the burners shut off? Does the T&P valve dump while in operation or on shutdown? Have you checked the firing rate of the boiler by either clocking the gas meter or by a connecting a manometer to the burner manifold? Is the system properly sized for the load? Are there any additional unused tappings on the storage tank and if so what size?


Not a plumber.. won't post intro as per request.


----------



## Protech

rjbphd said:


> Not a plumber.. won't post intro as per request.


I'm going to have to agree with ILP. This place just isn't what it use to be. 14 posts and still no content from anyone as to what the problem is...


----------



## rjbphd

Protech said:


> 35-38 degress


As I'm trying to remember of the calls I've b een on, one of them had the lower nipple twisted to wrong position allowing incoming water short circut to outlet.. usually there a black marker line on incoming nipple supposed to be in 12:00 position..


----------



## Protech

rjbphd said:


> As I'm trying to remember of the calls I've b een on, one of them had the lower nipple twisted to wrong position allowing incoming water short circut to outlet.. usually there a black marker line on incoming nipple supposed to be in 12:00 position..


I checked the top nipple and it was correct. I DID NOT check the lower nipple though. That is exactly what I told the manager when I was there. It's acting like the water is short circuiting and not stratifying. 

I bet that's it.


----------



## redbeardplumber

Was that it protech???


----------



## Plumbworker

So is the issue that the tank aquastat will never reach 180 set point or youre having issues recovering the tank while in use? First thing that came to my head was that a 120gal tank is pretty small for 20gpm of 180 degree water drawing continiously.. Is Lochniovar saying that their boiler will heat a 120gal tank with continuious 20gpm flow? Whats the delta t across the heat exchanger? you claim the pump is probably running "100gpm" but as per the manual the max flow rate is to not exceed 30gpm?


----------



## rjbphd

Hey ProTech.... we are all waiting for your result!! Do I have to find you somewhere else????


----------



## Plumbworker

I'm thinking theres a over pumping issue here..Too much flow through the heat exchanger and not getting enough heat transfer.. One question is was the pump replaced with the new boiler or is it the original?


----------

