The Multispan MHC-512 is a digital ON/OFF humidity controller with dual 10 A relays (control + alarm) and a 0–100% RH range, used across UAE incubators, cold and dry storage, pharma, HVAC, greenhouses and textile plants.
What is the Multispan MHC-512 humidity controller?
The Multispan MHC-512 is a digital panel-mount humidity controller that measures relative humidity and switches two 10 A relays to hold a room, chamber or duct at a set RH. Made by Multispan Control Instruments Pvt. Ltd. (India, manufacturing since 1986), it reads humidity through a factory-set RH-85 or RH-100 sensor and displays the live value on a 3-digit, 0.62-inch 7-segment display. Relay 1 controls humidification or dehumidification; relay 2 is a dedicated high/low alarm. It is CE certified, carries ordering code MHC-512-B1-01-W, and is stocked in Dubai by Al Misbah Al Sehri, the authorized Multispan distributor for the UAE and GCC. It suits any process where humidity must stay within a fixed band.
MHC-512 key specifications (dual 10 A outputs)
The MHC-512 provides two independent relay outputs rated 10 A each: relay 1 for humidification/dehumidification and relay 2 for a high/low alarm. It measures 0 to 100% RH (subject to sensor type) at 0.1% RH resolution with ±1% FSD accuracy, using an RH-85 or RH-100 sensor set at the factory. Control action is ON/OFF with adjustable hysteresis from 0.1 to 20 and an offset trim of -9.0 to +9.0 for field calibration. Auxiliary supply is 230V AC 50/60 Hz, 24V DC or 12V DC, drawing 3VA maximum. The body is 37 x 78 x 70 mm with a 30 x 71 mm panel cutout, and two LEDs indicate relay status. This makes it a compact, wide-supply unit for UAE control panels.
MHC-512 applications in UAE incubators and hatcheries
In UAE poultry incubators and hatcheries, the MHC-512 holds humidity in the 45–65% RH band that egg incubation and hatching require, using relay 1 to switch an atomiser or pad humidifier and relay 2 to alarm on drift. Egg viability depends on stable RH, so the controller's 0.1% RH resolution and ±1% FSD accuracy help maintain consistent hatch rates. The high/low alarm warns staff before humidity leaves the safe range, and the -9.0 to +9.0 offset lets operators calibrate the reading against a reference hygrometer. With 230V AC or 24/12V DC supply options, it drops into existing incubator panels across poultry farms in Al Ain, Ras Al Khaimah and the Northern Emirates.
Cold storage, dry storage and pharma humidity control
For cold rooms, dry stores and pharmaceutical areas, the MHC-512 keeps humidity within the narrow limits that protect stored product and comply with GMP and HVAC design intent. In cold storage it prevents both dehydration and condensation on produce; in dry stores for spices, grain, dates and dry goods it triggers dehumidification when RH climbs in the humid Gulf climate. Pharmaceutical stores and clean rooms typically target 45–60% RH, and the alarm relay flags excursions for the batch record. The unit's ±1% FSD accuracy and 0.1% RH resolution support tight control, while the CE-certified build and 230V AC / 24V DC / 12V DC supply suit UAE and DEWA-compliant panel work in Dubai and Abu Dhabi.
HVAC, greenhouses, mushroom farming and textile use
Beyond storage, the MHC-512 is widely used in HVAC air handling units, greenhouses, mushroom farms and textile plants. In AHUs it stages a steam or spray humidifier or a dehumidifier to hold supply-air RH. Greenhouses and mushroom growing rooms across the UAE run high, stable humidity (often 80–95% RH for mushrooms), which the controller maintains via relay 1 with the alarm guarding the crop. Textile weaving, spinning and paper conditioning halls need controlled RH to reduce yarn breakage and static, and the MHC-512 switches the plant's humidification system to hold that setpoint. Its ON/OFF control with adjustable hysteresis prevents rapid relay chatter across all of these loads.
How to set up and wire the MHC-512
Setting up the MHC-512 means mounting it, wiring the supply and sensor, then entering a setpoint and hysteresis. Fit the controller into a 30 x 71 mm panel cutout and secure the clamps. Connect the auxiliary supply to the correct terminals for your version (230V AC, 24V DC or 12V DC) and wire the factory-set RH-85 or RH-100 sensor to the input. Wire the humidifier or dehumidifier contactor to relay 1 and the alarm/annunciator to relay 2, keeping loads within the 10 A rating (use a contactor for larger plant). Set the desired RH, adjust hysteresis (0.1 to 20) to avoid short-cycling, and use the offset (-9.0 to +9.0) to match a reference meter. Always follow the Multispan datasheet supplied with your unit.
MHC-512 vs MHT-1202/MHT-9044 and TC-510: which to choose
Choose the MHC-512 when you need humidity-only control with two 10 A outputs; step up to the MHT series when you need humidity and temperature together. The MHC-512 controls RH alone with one control relay plus an alarm relay. The Multispan MHT-1202 and MHT-9044 combine humidity and temperature control in one unit and add RS-485 Modbus for BMS integration, making them better for chambers where both variables matter or where data logging is required. The Multispan TC-510 is a temperature-only universal PID/ON-OFF controller. For incubators, cold stores or textile halls that regulate humidity by itself, the MHC-512 is the direct, cost-effective fit; specify the MHT range for combined climate control. Al Misbah Al Sehri stocks all three in Dubai.
Where to buy the MHC-512 in the UAE
Buy the genuine Multispan MHC-512 in the UAE from Al Misbah Al Sehri, the authorized Multispan distributor for the UAE and GCC, based in Dubai. As the authorized distributor, we supply factory-sourced units (ordering code MHC-512-B1-01-W) with manufacturer warranty, datasheet and CE certification, not grey-market stock. We deliver across all seven emirates — Dubai, Abu Dhabi, Sharjah, Ajman, Ras Al Khaimah, Fujairah, Umm Al Quwain and Al Ain — plus the wider GCC (Saudi Arabia, Qatar, Oman, Kuwait, Bahrain) and worldwide export. For current price, stock and the full datasheet, quote model MHC-512 by phone on +971 4 320 3957 or email sales@misbahswitchgear.com, or use the Request a Quote form on the product page.
