Honeywell TP970 Series User Manual

77-9382-1
TP970 and TP9600 Series
Pneumatic Thermostats
Copyright © 1997 Honeywell Inc. • All Rights Reserved
ENGINEERING DATA
Contents
Introduction .............................................................................................................................. 2
Fundamentals of
Thermostat Operation .............................................................................................................................. 2
General................................................................................................................. 2
Flapper-Nozzle Operation.................................................................................... 2
Valve Unit Operation ............................................................................................ 2
TP973A, B and TP9630 A, B
Low-Capacity, Single-Temperature
Thermostats .............................................................................................................................. 4
General................................................................................................................. 4
Operation.............................................................................................................. 5
Direct Action.................................................................................................. 5
Reverse Action.............................................................................................. 5
TP970A-D and TP9600A, B
High-Capacity, Single-Temperature
Thermostats .............................................................................................................................. 6
General................................................................................................................. 6
Operation.............................................................................................................. 6
Direct Action.................................................................................................. 6
Reverse Action.............................................................................................. 7
TP971A-C and TP9610A, B
High-Capacity, Dual-Temperature
Thermostats .............................................................................................................................. 7
TP971B and TP9610B ......................................................................................... 7
TP971C ................................................................................................................ 7
TP971A and TP9610A ......................................................................................... 7
Daytime Operation ............................................................................................... 8
Nighttime Operation ............................................................................................. 8
Manual DAY Override........................................................................................... 9
TP972A and TP9620A High-Capacity,
Heating/Cooling Thermostat .............................................................................................................................. 10
General................................................................................................................. 10
Operation.............................................................................................................. 12
TP974A Room
Temperature Sensor .............................................................................................................................. 12
General................................................................................................................. 12
Operation.............................................................................................................. 12

Honeywell TP970 Series Specifications

General

Brand	Honeywell
Model	TP970 Series
Category	Thermostat
Language	English

Summary

Introduction to Pneumatic Thermostats

Fundamentals of Thermostat Operation

Provides foundational principles of thermostat operation, including force-balance design and key components.

Flapper-Nozzle Operation

Explains the mechanism where a bimetal force balances feedback pressure through a nozzle.

Valve Unit Operation

Details how the valve unit amplifies airflow for controlling actuators using pilot pressure.

TP973A, B and TP9630A, B Low-Capacity Thermostats

General TP973/TP9630 Overview

Introduces the TP973/TP9630 series as the simplest models, detailing their basic configuration.

TP973/TP9630 Operation

Describes how the TP973/TP9630 models function, including their use with restrictors and two-pipe systems.

TP973/TP9630 Direct Action Operation

Explains the direct-acting mode where increasing temperature increases signal pressure.

TP973/TP9630 Reverse Action Operation

Explains the reverse-acting mode where increasing temperature decreases signal pressure.

TP970A-D and TP9600A, B High-Capacity Thermostats

General TP970/TP9600 Overview

Describes these models as high-capacity versions of the TP973, incorporating a valve unit for greater control.

TP970/TP9600 Operation

Details the operation of TP970/TP9600 high-capacity thermostats, focusing on pilot-operated mechanisms.

TP970/TP9600 Direct Action Operation

Explains the direct-acting behavior for high-capacity models, where temperature rise increases pressure.

TP970/TP9600 Reverse Action Operation

Explains the reverse-acting behavior for high-capacity models, where temperature rise decreases pressure.

TP971A-C and TP9610A, B Dual-Temperature Thermostats

General TP971/TP9610 Overview

Introduces dual-temperature models with separate day/night sensing elements and setpoints.

TP971B and TP9610B Models

Specifies that these are reverse-acting versions of the TP971A/TP9610A models.

TP971C Model

Describes the TP971C as a direct-acting, three-pipe thermostat for auxiliary control.

TP971/TP9610 Day/Night Operation

Daytime Operation

Explains airflow and operation under lower main air pressure (13 psi) for daytime control.

Nighttime Operation

Explains airflow and operation under higher main air pressure (18 psi) for nighttime control.

Manual DAY Override for TP971/TP9610

TP972A and TP9620A Heating/Cooling Thermostats

General TP972A/TP9620A Overview

Introduces high-capacity thermostats with two bimetal elements for heating and cooling control.

TP972A/TP9620A Cooling Cycle Operation

Explains operation when the cooling bimetal controls the system under lower main air pressure.

TP972A/TP9620A Heating Cycle Operation

Explains operation when the heating bimetal controls the system under higher main air pressure.

TP974A Room Temperature Sensor

General TP974A Sensor Overview

Describes the TP974A as a bimetal sensor for two- or one-pipe systems, with direct-acting properties.

TP974A Sensor Operation

Details how the TP974A sensor interacts with an RP920A controller for heating valve operation.