Problem & Cause
Answer
A. Fluctuating or erratic hot water temperature at fixture.
A.1 Heavy draws of either cold or hot water elsewhere in
the system, such as clothes washer or dishwasher.
A.1 See warning on reverse side. Hot water temperature control valves cannot compensate
for this condition. Check valves in hot and cold legs to hot water temperature control valve
would help but not cure the problem.
A.2 Unbalanced pressures.
A.2 Install balancing or throttling valves (shutoff valves) in hot and cold legs to hot water
extender tempering valve and adjust accordingly for demand.
B. Hot water backing up into cold water line.
B. Hot water pressure overriding cold pressure.
B. Install check valve in cold water leg to hot water temperature control valve.
C. Cannot adjust water temperature to desired temperature.
C.1 Unequal pressures.
C.1 A balancing or throttling valve must be installed in the cold water leg to the hot water
temperature control valve to throttle or restrict the pressure. In most installations, the cold
water supply line feeds both the hot water temperature control valve and the water heater
or tankless heater. To compensate for the pressure drop through the heater, the cold
water to the hot water temperature control valve must be throttled or reduced.
C.2 Hot or cold temperature differential.
C.2 Check water heater controls to verify that the water temperature is the same as the
heater thermostat setting.
C.3 Valve undersized.
C.3 Check gpm flow required versus gpm flow capacity of valve.
D. High pressure drop through hot water temperature control valve.
D. Valve undersized.
D. Install larger hot water temperature control valve.
E. Insufficient hot water during peak demand
E.1 Valve undersized.
E.1 Check gpm flow required during peak demand period and size hot water temperature
control valve accordingly.
E.2 Heater or capacity insufficient for demand.
F. Frequent failure of thermostatic element.
F.1 Thermostatic element exposed to extremely high
temperature.
F.1 Check heater thermostat setting.
F.1a Hot water temperature control valve must be trapped at least 8” to 12” as per installa-
tion instructions. Install check valves as recommended.
F.2 Corrosive water conditions. (Buildup of mineral
deposits)
F.2 Frequent cleaning of thermostat element and plunger would tend to prolong the life of
the element. A small coating of FDA approved silicone lubricant in the piston area of the
element would also help.
F.3 Electrolysis (pitting deterioration, etc.)
F.3 Electrically ground the piping system or install dielectric unions.
G. All hot or cold water flows at hot fixture.
G.1 This problem will require considerable trouble-
shooting.
G.1 Verify that complete installation instructions were followed:
A. Is valve properly trapped?
2. Check to see if thermostatic element has failed.
3. Check to see if temperature control on water heater is set at desired
temperature.
4. Check to see if minimum flow requirements for valve size are met. Minimum flow
requirements for LF70A series valves is 2 gpm.
Series LF70A Troubleshooting Guide
NOTICE
After installation please leave this instruction sheet for
occupant’s information.
Limited Warranty:
Watts Regulator Co. (the “Company”) warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of
original shipment. In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.
THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT. THE COMPANY MAKES NO OTHER
WARRANTIES, EXPRESS OR IMPLIED. THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
The remedy described in the first paragraph of this warranty shall constitute the sole and exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental, special
or consequential damages, including without limitation, lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly, other costs resulting
from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemical, or any other circumstances over which the Company has no
control. This warranty shall be invalidated by any abuse, misuse, misapplication, improper installation or improper maintenance or alteration of the product.
Some States do not allow limitations on how long an implied warranty lasts, and some States do not allow the exclusion or limitation of incidental or consequential damages. Therefore the above
limitations may not apply to you. This Limited Warranty gives you specific legal rights, and you may have other rights that vary from State to State. You should consult applicable state laws to
determine your rights.
SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO ONE YEAR FROM THE DATE OF ORIGINAL SHIPMENT.
WARNING:
This product contains chemicals known
to the State of California to cause cancer and birth
defects or other reproductive harm.
For more information: www.watts.com/prop65
IS-70A 1548
EDP# 1910210
© 2015 Watts
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Tel: (978) 689-6066 • Fax: (978) 975-8350 • Watts.com
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Tel: (905) 332-4090 • Fax: (905) 332-7068 • Watts.ca
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