Help with laars Endurance EBP 175

ArchimoreHorie

Can someone help me with a Laars Boiler.
First no hot water. Replace flow switch. Same problem. F-4 code. Replace supply sensor.
Refill unit with water.. start boiler. Lots of noise. High pressure. Pressure valve release with lots of steam and shut down. No codes. Check and found pump not working. Replace pump. Start unit up. Unit run for 5 minutes and shut down. No codes. Found power strip. Reset start up and run until unit say 161 and go into sleep. After 2 minutes. It start up again run until it say 161 and shut down. No codes. Help.

EdTheHeaterMan

I believe the 161 you are f=referring to is the boiler water temperature. If that is true, the normal sequence of operation for the combination heat and hot water EBP will stop the gas flame at 158° if there is no call for heat.

from page 22 of the manual:
The EBP modulating combination boiler will
start from any of three input signals: (a)T-T closure
for space heating. (b)A demand for domestic hot
water, signaled by water flow activation of the water
flow switch. (c)A call for heat from the minimum
tank temperature sensor at 158°F (tank charge mode).
In tank charge mode the red LED located below the
green LED on the PCB will be lit. In modes (b) and
(c) which are priority modes, the internal anticondensing valve will be closed. On a T-T call for
heat the valve will remain closed until the priority
modes are satisfied

In this mode if there is no call for heat, the system will cycle on the limit temperature of 158° (and possibly over shoot to 161°) until the water tank is charges with hot water and the hot water priority is satisfied.

If there is a call for heat, the tank must be charged until the hot water priority is satisfied, then the space heating can commence.

hot_rod

Sounds like an air lock in the boiler. How are you purging it when you refill?

EdTheHeaterMan

do you have the manual? the trouble shooting is in there. https://www.parts4heating.com/v/vspfiles/images/pdfs/EdpEbpManual.pdf
A couple of things that may still be wrong
Can you confirm that your system is properly piped and that there is no air in the piping system?

OR

These piping arrangements use a system circulator(s) for space heating. They do not utilize the internal Boiler circulator for space heating.
Is (are) the system circulator(s) operational?

ArchimoreHorie

Thanks for responding. I have this system from 2004. Piping is ok
I have pipe running up stair to get hot water. Hot water run for 5 minutes and go off and comes back on again for 5 minutes.
Heat is on. Boiler is cycle every 5 minutes.
I bleed the coin valve two of them. I then bleed the heater line.

EdTheHeaterMan

@ArchimoreHorie OK then there is heat getting to the radiators? Yes or No

ArchimoreHorie

Yes
But i believe the boiler is short cycle. Why the hot water is getting cold

ArchimoreHorie

Heat is getting to the base board ok. Circulating pump is working ok

EdTheHeaterMan

Good. the problem is in the priority on the DHW. Let me look at the manual for a possible cause.

EdTheHeaterMan

One cause could be the flow switch. This switch lets the boiler control know that there is hot water being used. the control goes into a DHW priority mode and stops space heating and also uses the internal boiler circulator pump to take heat from the boiler and direct it into the DHW heat exchanger. If the flow switch drops out during the use of hot water. the boiler control will thing the hot water was turned off and direct the boiler hot water to space heating or shut down the burner if there is no call for heat. It sound as like the 5 minute short cycling is happening during a "no call for heat" situation so the burner stops. then it has to go thru the start up sequence to relight.

Still checking for more. don't order the Flow switch yet.

EdTheHeaterMan

Two other possibilities for short cycling. Contamination of flue gas into the combustion air inlet. this is for Direct vent systems only. Does your system have 2 pipes to the outdoors for the venting. Or the concentric vent where both pipes go thru a bigger opening?
Example of concentric vent:
If one of the exhaust pipes has a leak and the exhaust is getting into the combustion air intake, then you get this cross contamination that can cause short cycling.

Look for a damaged vent pipe. inside and outside

The other one is the anti condensation valve on the EBP models may be stuck. it is #17 0n thei illustration Try tapping on this with a small hammer or a wooden mallet for tenderizing meat.
Be firm but gentile. If that corrects the problem, then order this kit:
VALVE, ANTI CONDENSING, REPAIR KIT 2400-538
If the vent leak (could not find a vent leak issue) or the anti condensing valve (tapping on valve does not make a difference) are not the problem then you probably need the flow switch.

I would order both the flow switch and the valve kit if I was in your situation. Since both require draining the boiler, then is would do both at the same time.

Disclaimer: The last time I worked on one of those was 2011. My memory on this product is limited to only 2 different customers. Neither had your issue.

I hope this helps

ArchimoreHorie

Ok. New flow switch. I have two vent pipe. One of the vent pipe that fix on the burner did come loose. I tape it with aluminum tape. To secure it.

EdTheHeaterMan

ArchimoreHorie said:

Ok. New flow switch. I have two vent pipe. One of the vent pipe that fix on the burner did come loose. I tape it with aluminum tape. To secure it.

What is the pipe made of? PVC plastic? stainless steel? Metal tape is not a permanent fix.
Flow switch and the other anti Condensation kit. If tapping on the part 17 gets that to move the way it is supposed to then you have narrowed it down.

ArchimoreHorie

I will try that in the morning.

ArchimoreHorie

No more short cycle. But DHW is still on and off. Sometimes hot then. Cold