Fault Diagnosis - Mira EXCEL Installation & User Manual

Read the section: Important Safety Information first.
Provided that the BSM has been correctly installed and is operated in accordance
with the instructions contained in this guide, difficulties should not arise. If any
maintenance is required then it must be carried out by a competent tradesperson for
whom the fault diagnosis chart and maintenance instructions are provided. Before
replacing any parts make sure that the underlying cause of the malfunction has been
identified.
Symptom
1. Only hot or cold
water from mixer
outlet.
2. Fluctuating or
reduced flow.
3. No flow from mixer
outlet.
4. Blend temperature
drift.
5. Maximum blend
temperature setting
too hot or too cold.

FAULT DIAGNOSIS

a. Inlet supplies reversed. Make sure that the hot
supply is connected to the left, and the cold supply
to the right hand inlet when viewed from the front.
b. The thermostatic cartridge (1598.022) is fitted
incorrectly. Make sure that the hot inlet (marked 'H')
is on the left side.
a. Check that the inlet filters are not blocked.
b. Make sure that the minimum flow rate is sufficient
for the supply conditions.
c. Make sure that the maintained inlet pressures are
nominally balanced and sufficient.
d. Make sure that the inlet temperature differentials
are sufficient.
e. Check the thermostatic performance.
f. Flow regulators fitted incorrectly.
g. Airlock or partial blockage in pipework.
a. Make sure that the inlet isolating valves are open.
b. Hot or cold supply failure. Make sure that the hot
and cold supplies are available to the mixer.
c. Refer to symptom 2. above.
a. Make sure that the inlet valves are open.
b. Hot supply temperature fluctuation.
c. Supply pressures fluctuating.
d. Thermal Cartridge defective.
e. Inlet Filters Blocked.
a. Indicates incorrect maximum temperature setting,
refer section: 'Commissioning'.
b. Refer to symptom 4. above.
18
Cause/Rectification