Table of Contents
Advertisement
5.3 Troubleshooting
Circulation Pump Deadhead
Deadheading occurs when the circulation pump is unable to deliver any flow. Ensure that any isolation
valves installed in the system are OPEN. It may be necessary to slightly restrict isolation valves on the
pump discharge to achieve the desired flow rate, but they should never be completely closed unless the
unit is turned off and being serviced.
Circulation Pump Cavitation
Cavitation occurs when the water pressure at the suction side of the pump is below the pump's required
suction head pressure. Ensure that any isolation valves on the suction side of both circulation pumps are
OPEN. Also, ensure that there is a sufficient static fill pressure of the system. Refer to
3.4.7
for more information on the expansion tank/fill valve assembly. If there are any strainers on the
domestic circulation line, these may be clogged and should be thoroughly cleaned to restore flow.
NURO Error 10203: "Delta T Limit has been reached"
appliance requires sufficient water flow at all times in order to operate safely. A "Delta
®
The P-K MACH
T Limit has been reached" error indicates the appliance's supply temperature has departed too far from
the appliance's return temperature. This is usually due to insufficient water flow on the appliance loop.
Ensure that all of the isolation valves are open and that the circulating pumps aren't deadheading or
cavitating.
NURO Error 10204: "Maximum Outlet Temperature Reached"
®
The P-K MACH
appliance requires sufficient water flow at all times in order to operate safely. A
"Maximum Outlet Temperature Reached" error indicates the appliance's supply temperature is above the
maximum allowable value. This is usually due to insufficient water flow on the appliance loop. Ensure
that all of the isolation valves are open and that the circulating pumps aren't deadheading or cavitating.
NURO Errors 10014 or 10015: "Start Interlock Open"
In the event the high temperature limit aquastat trips, the appliance's START INTERLOCK #1 circuit will
open. Ensure that all of the isolation valves are open and that the circulating pumps aren't deadheading
or cavitating. Once the source of the high water temperature has been identified, reset the high
temperature limit.
NURO Error 10010: "Low Water Limit"
The appliance loop must be completely full of water at all times in order to operate. The P-K MACH
appliance features a low water cutoff probe that will put the appliance into alarm if water is not detected
inside the appliance's heat engine. Check the water pressure on the appliance piping to ensure there is
a sufficient water pressure. Also, ensure the automatic air vents are able to purge any air that has
accumulated within the appliance. Refer to
MACH appliance.
Poor Heat Transfer
Poor heat transfer can be caused by insufficient flow, insufficient appliance water temperature, or scaling
of the heat exchanger. First, ensure that both the appliance side and domestic side circulation pumps
are moving water at the desired rate. Next, increase the appliance's setpoint in small increments to
ensure there is sufficient temperature to produce the desired domestic water temperature. If these two
steps are unable to restore heat transfer, it may be necessary to clean or replace the brazed plate heat
exchanger.
Revised: January 3, 2020
Released: January 3, 2020
Sections 3.3.4
&
Patterson Kelley 2020
All Rights Reserved.
®
P-K MACH
Gas Fired Appliance
Technical Service 1.877.728.5351
3.4.7
for instructions on filling the P-K
1004905989 MnR & MnRP 300-399-500-750-
1050 NURO Rev C (Jan-2020).docx
Sections 3.3.4
&
®
Page 35
Advertisement
Table of Contents
