Frequently Asked Questions

What are your business hours?

We are open Monday - Friday 8:00 AM to 5:00 PM EST / EDT. You can easily reach us via telephone at 215-355-8400 or via email at:

When I contact your office for assistance on a product I purchased, what information do you need from me?

The most successful way to get help from our technicians is to have your serial number for the flow meter or flow switch you need assistance with. This will greatly help our technicians quickly research and resolve your question or issue.

How do I return a flow meter for re-calibration, warranty, or other service work?

Package the flow meter(s) and send to our address below with the following information: Contact Name, Phone, Email, Return Address, PO# (If required), and Reason for Return (i.e. Recalibration, Need Certificate, As Found / As Left, etc.

Thermal Instrument Company
Attn: Repairs/Recalibrations
217 Sterner Mill Road
Trevose PA, 19053 USA

Do I need an RMA number?

No. We do not require RMA numbers to return meters. If you are required to have an RMA number then just use the Serial Number of the meter(s) since they are unique to the meter(s). Our Serial Numbers can be found on a metal tag on the back of the condulet or etched onto the body of the flow meter.

What is the turn-around time on a returned meter?

Typical return time is about 3 to 4 weeks. If you require a faster turn-around time, note the requirement on the paperwork that will be sent with the meter and we will do our best to accommodate.

How long does it take to receive a new flow meter once I place my order?

Typical delivery is 4 - 6 weeks from the time a PO# is issued and an order acknowledgement is received. However, we can offer an expedited solution depending on the requirements and specifications of the application. Please contact us to see if we can offer an expedited solution.

How will my order be shipped to me?

We ship our orders via UPS. We have arrangements with FedEx, DHL, and numerous other carriers if you have a preference.

What is your procedure on checking the calibration of a landfill gas meter in the field?

Field Procedure for Landfill Gas Calculation using a Pitot Tube
First calculate the average flow rate, in inches of water column, by taking a traverse of the flow line with a pitot tube. A set of 10 or 20 traverse flow points can be done. The traverse flow point locations are calculated by 5 formulas: 0.316 R, 0.548 R, 0.707 R, 0.837 R, and 0.949 R, with R being the radius of the inner dimension of the flow line. These 5 locations are from the center of the line and with these 5 locations on each side of the center, you get the 10 flow points needed to calculate the average flow rate. If needed, these flow points can be done both horizontally and vertically to achieve a total of 20 flow points in a line. Afterwards, calculate the total molecular weight by taking the volumetric percentages of the three major gases in a landfill gas flow, Methane, CO2, and Oxygen, and multiply them with each of the gasses molecular weight and add the results. The rest of the landfill gas flow percentage is left as Balance, or Air, and that is multiplied with the molecular weight of Air and added to the above results.

Example: 40% Methane, 40% CO2, 1% Oxygen, and 19% Balance.
Methane = 16.043 X 0.4 = 6.4172
CO2 = 44.01 X 0.4 = 17.604
Oxygen = 32.00 X 0.01 = 0.32
Balance = 28.964 X 0.19 = 5.50316
The total molecular weight = 6.4172 + 17.604 + 0.32 + 5.50316 = 29.84436

Next the density is calculated by the ideal gas equation P / RT = Density
P = Line pressure (PSIA) X 144
R = 1545.33 / molecular weight
T = Line temperature (°F) + 460 = °R
Example: Line pressure = 3 PSIG = 17.7 PSIA
Line Temperature = 110°F
P = 17.7 X 144 = 2548.8
R = 1545.33 / 29.84436 = 51.7796
T = 110 + 460 = 570
Density = 2548.8 / (51.7796 X 570) = 0.08636 lbs/ft³

Next the velocity is converted into feet per minute by V = 1096.7 X Square root (hv / d).
hv = velocity in inches of water column
d = calculated density
Example: Average flow rate = 0.85 inches of water column.
V = 1096.7 X Square root (0.85 / 0.08636) = 3440.65 FPM

Next the above feet per minute velocity needs to be corrected for standard flow rate by
using the Combined Ideal Gas Law V2 = V1 X (P1 / P2) X (T2 / T1).
T = temperatures in °K = °C + 273
P = pressures in PSIA.
T2 = 60°F (standard) = 288.56°K
T1 = Line temperature in °K
P2 = 14.7 PSIA (standard)
P1 = Line pressure in PSIA
Example: Line pressure = 3 PSIG = 17.7 PSIA
Line temperature = 110°F = 316.33°K
Corrected velocity = 3440.65 FPM X (288.56 / 316.33) X (17.7 / 14.7) = 3779.13 FPM

Now the flow rate can be calculated into SCFM by multiplying the above to the line’s
inside cross sectional area (in square feet).
Example: Line ID = 12.39” = 0.8373 FT²
Flow rate = 3779.13 X 0.8373 = 3164.27 SCFM.

What is the calibrated gas mixture for your Landfill Gas meters?

Our Landfill Gas meters are calibrated to a wet basis of 50/50 percentage mixture of Methane and CO2 with a tolerance of +/- 10% variance

What are the standard conditions used for landfill meters?

Landfill gas is calibrated to 60 F at 1 ATM unless otherwise stated in the calibration data.

What temperature range are Landfill gas meters calibrated to?

Standard landfill gas meter temperature range is 40 to 200 F, unless requested otherwise.

What are the straight run requirements?

Our meters require 10 pipe diameters upstream and 5 pipe diameters downstream of straight run.
If you feel the best location you have for a meter is under this requirement then just let us know. We can calibrate a meter with your plumbing situation but it will be only good for just that location.

What is the proper installation of the 62-9 Probe Insertion Meter?

Minimum of 10 pipe diameters of straight run ahead of the meter and 5 pipe diameters after.

Meter can be mounted on top of the line, 12 o'clock position, or through the sides of the line, 3 or 9 o'clock position. but not up through the bottom of the line.

Meter can be mounted in a vertical or horizontal line.

For Serial Numbers of 2011xxx or less, the probe is mounted in the line with the face of the arrow facing up-stream. The arrow is etched on the probe shaft just underneath the condulet head.

For Serial Numbers of 2012001 or higher, the probe is mounted in the line with the arrow pointing in the direction of flow. The arrow is etched on the fitting just underneath the condulet

The insertion length of the probe inside the line is:

Line Sizes 1 1/2" to 2" - Gently insert to bottom of line then withdraw 1/8"
Line Sizes 2 1/2" to 7" - Gently insert to bottom of line then withdraw 1/4"
Line Size > = 8" - Insert halfway into line then insert 3" more

Can the 600-9 In-line flow element be mounted in a vertical line?

Yes, but only with flow going up.

What do you recommend for calibration frequency?

If you are using the flow meter instrument for compliance reporting we recommend recalibration every 18 months to insure that your reported numbers have been validated against a NIST calibration standard. We can provide a certificate of calibration to help you maintain a physical record of this recalibration.

That being said, we have thousands of units out in the field being used across numerous flow applications measuring fluids that only come back for recalibration periodically at customer discretion. In these cases, the customers have sent units back when they start to question the readings being generated by their process. Our flow instruments are very durable, however, some applications are more harsh than others with regards to particle build up on instruments, exposure to high temperatures, or the use of harsh chemicals. Over time, with any electronic instrument, components can go bad or their performance may deteriorate, so in these cases we defer to the specific customer as they know their application best.

Does moisture affect the indication of your meters?

Our meters are good with moisture up to the point where it forms droplets onto the sensor location on the meter. Moisture droplets will cause the meter to indicate high and noisy until the droplets either fall off or evaporate, which then the meter will indicate back to normal.

Are the meters temperature compensated?

Yes. All of our meters are calibrated with temperature compensation to the temperature minimum and maximum conditions where the meter will be installed.

Does pressure affect your meters?

Pressure has no affect on our flow meters calibrated for liquids. For meters calibrated for gases, pressure has to change more than (+/-) 15 ATM before affecting meter output. We do need to know the maximum pressure where the meter will be installed to make sure the meter will have the proper and safe process connection.

What are the standard calibration conditions used for your meters?

Our standard is 70 F at 1 ATM unless otherwise stated.

Does the mA output on remote electronics Model 926 need power?

No. The mA output is self powered. No external power needed.

Does the mA output on remote electronics Model 9200 need power?

Yes. This Model does come with a 24 VDC power supply that you can use for the mA output or you can use a 24 VDC power supply of your own.

Do I need to wire up both sets of 110 VAC connections to the 9200B?

Yes, you will need to wire both sets of connections to 110 VAC. One set is for the 9200B itself while the other is for powering up the flow element. You can just simply jumper the two sets if you only have one 110 VAC available.

How is your Modbus RS 485 output option configured?

Modbus ASCII and Modbus TCP are not supported. Naming conventions for the RS-485 interface are per the latest revisions of the Modbus over Serial Line Specification and Implementation Guide V1.02 and the Modbus Application Protocol Specification V1.1b3. 

RS-232 Communications settings
The meter is preconfigured for serial communications at 9600 baud, even parity, 8 data bits, 1 stop bits. These settings can be changed in the field by using the TICO Parameter Setup Utility software tool.

Slave ID
The unit is shipped from the factory with the Slave ID set to 1.  This setting can be changed in the field by using the TICO Parameter Setup Utility software tool.

Modbus Function Codes Supported
The only function supported in this version is the Read Holding Register, as described below. 

Reg Type Modbus Addr Data Type Description
Holding 40001 Float Mass flow in Eng Units
Holding 40002 Float Mass Flow in Eng Units
Holding 40003 Float Mass Total in Eng Units
Holding 40004 Float Mass Total in Eng Units

The float values are sent in the normal order mode as accepted by most Modbus masters.  The float values can be changed to Swap Word Order, Swap Byte Order, or Swap Both Word and Byte Order by using the TICO Parameter Setup Utility software tool.



What Pulse Output options are offered on 9500 Electronics?

Standard Configuration
12 Volt DC pulse with a 20 millisecond on time and one pulse per specified flow range.

The three variables or options are:
Option #1 - Voltage pulse or dry contact closures output
Option #2 – Length of pulse 20 millisecond standard. Can be shorter or longer. For example, 5 millisecond, 100 millisecond, 1 second. Etc.
Option #3 - Pulses per unit of Flow rate. For example, 1 pulse per flow unit, 10 pulses per flow unit. Etc.
The three variables cannot be changed in the field, therefore Thermal Instrument Co. needs to know exact variables needed to accommodate the equipment interface. 

What is your warranty period?

(1) Thermal Instrument Co. warrants that the products furnished under this Agreement will be free from defects in material and workmanship for a period of four years from the date of shipment.  The customer shall provide notice of any defect to Thermal Instrument Company within one week after the Customer’s discovery of such defect.  The sole obligation and liability of Thermal Instrument Company under this warranty shall be to repair or replace, at its option and discretion, without cost to the Customer, the defective product or part.

(2) Upon request by Thermal Instrument Co, the product or part claimed to be defective shall immediately be returned at the Customer's expense to Thermal Instrument.  Replaced or repaired products or parts will be shipped to the Customer at the expense of Thermal Instrument.  Thermal Instrument Company shall have the right of final determination as to the existence and cause of defect.

(3) There shall be no warranty or liability for any products or parts that have been subject to misuse, accident, negligence, acts of God, lightning strikes, flooding, or failure of electric power or modification by the Customer without the written approval of Thermal Instrument.  This warranty does not cover damage caused by customer’s exposure of the goods to corrosive or abrasive environments.  Final determination of warranty eligibility shall be made by Thermal Instrument Company.  If a warranty claim is considered invalid for any reason, the Customer will be charged for services performed and expenses incurred by Thermal Instrument in handling and shipping the returned unit.

(4) The liability of Thermal Instrument Company shall be limited to replacing or repairing, at its option, any defective parts which are returned.  Labor and related expenses incurred by the Customer to install replacement parts are not covered by this warranty.

(5) For replacement parts supplied or repairs made during the original warranty period, the warranty period for the replacement or repaired part shall terminate with the termination of the warranty period of the original product or part.

(6) The use of Thermal Instrument Company products are under exclusive control of the buyer. No warranty is given for the calibration, accuracy or workmanship of product into which Thermal Instrument Company products are installed.  Thermal Instrument Company can only be held responsible for the calibration and accuracy of the product supplied by Thermal Instrument themselves as the manufacturer.  Thermal Instrument Company specifically denies any liability arising from the buyer’s application of Thermal Instrument Company products including any physical injuries or death arising directly or indirectly out of or in connection with the manufacture, sale, use, or defect of the products sold hereunder.

(7) No warranty is made with respect to custom equipment or products produced to Buyer's specifications except as specifically stated in writing by Thermal Instrument Company and contained in the agreement.


Do you offer field service for flow meter re-calibrations & trouble shooting?

Yes. We have many customers that utilize our field service in order to minimize any down time in production at their site. Our Field Service Engineers will travel to your location, diagnose, re-calibrate or troubleshoot the problem, and have your operation running again in minimum time.  For our Landfill customers, we have the ability to provide on-site re-calibration and certificate services in order to maintain compliance with United States EPA regulations. Please contact Thermal Instrument at 215-355-8400 to schedule your on-site field service at your convenience.